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Substack Formatting Guide: Headers, Bold, Italic, and Everything In Between

Formatting

Substack’s editor is intentionally minimal. It gives you enough formatting tools to write a professional newsletter without overwhelming you with options. But understanding exactly what’s available — and what’s not — helps you make the most of every post.

This guide covers every formatting option in Substack’s editor, including keyboard shortcuts, best practices, and workarounds for features the editor doesn’t natively support.

Heading Levels

Substack supports three heading levels in the post body:

Heading 1 (Title)

Your post title is automatically formatted as H1. You set this in the title field at the top of the editor, not in the body content. There should only be one H1 per post.

Heading 2 (Section Heading)

H2 is your primary section heading within the post body. Use it to divide your post into major sections. In the editor, select text and click the large “H” button, or use the keyboard shortcut:

  • Mac: Cmd + Shift + 1
  • Windows: Ctrl + Shift + 1

Heading 3 (Subsection Heading)

H3 is a smaller heading for subdivisions within a section. Click the small “h” button or use:

  • Mac: Cmd + Shift + 2
  • Windows: Ctrl + Shift + 2

Heading Best Practices

  • Use a clear hierarchy: H2 for main sections, H3 for subsections within those sections
  • Don’t skip levels: going from H2 directly to plain text, then jumping to H3, confuses readers
  • Keep headings concise: 3-8 words is ideal for scannability
  • Use headings generously: newsletters sent by email benefit from clear section breaks since readers often skim

Bold Text

Bold draws attention to key phrases and helps readers scan your content.

Keyboard shortcut: Cmd/Ctrl + B

You can also select text and click the B button in the toolbar.

When to Use Bold

  • Key terms being introduced for the first time
  • Important numbers or data points
  • Action items or recommendations
  • Names of products, companies, or concepts central to your argument

When to Avoid Bold

  • Entire paragraphs (bold loses its emphasis if everything is bold)
  • Every sentence in a list (use it selectively)
  • For visual decoration — bold should signal importance, not style

Italic Text

Italic provides gentler emphasis than bold and signals specific types of content.

Keyboard shortcut: Cmd/Ctrl + I

When to Use Italic

  • Titles of books, films, publications, and other works
  • Foreign words or phrases
  • Introducing technical terms alongside their definitions
  • Internal thoughts or hypothetical dialogue
  • Gentle emphasis where bold would be too strong

Bold + Italic

You can combine both for strong emphasis. Select text and apply both bold and italic:

Keyboard shortcut: Cmd/Ctrl + B followed by Cmd/Ctrl + I

Use this sparingly. If you’re reaching for bold-italic frequently, your content may benefit from structural changes (like headings or bullet points) rather than text-level emphasis.

Strikethrough

Substack supports strikethrough text, which renders with a line through the middle.

Keyboard shortcut: Cmd/Ctrl + Shift + X

Strikethrough is useful for:

  • Showing corrections or updates inline
  • Humor (crossing out what you “really” wanted to say)
  • Indicating removed or deprecated items in a list

Note: strikethrough renders correctly on the web version but may not display consistently across all email clients. Test before relying on it for critical information.

Adding hyperlinks is one of the most important formatting actions in a newsletter.

Keyboard shortcut: Cmd/Ctrl + K

Select the text you want to link, press the shortcut, and paste the URL.

  • Use descriptive anchor text: “read the full report” is better than “click here”
  • Open in new tab: Substack handles this automatically for external links
  • Check your links: broken links erode reader trust — preview your post and click every link
  • Don’t overlink: 3-5 links per section is usually sufficient. Too many links feel like spam

Lists

Unordered (Bullet) Lists

Click the bullet list icon in the toolbar or:

  • Mac: Cmd + Shift + 8
  • Windows: Ctrl + Shift + 8

Press Tab to indent (create a nested list) and Shift + Tab to outdent. Substack supports one level of nesting.

Ordered (Numbered) Lists

Click the numbered list icon or:

  • Mac: Cmd + Shift + 7
  • Windows: Ctrl + Shift + 7

Numbered lists are ideal for sequential instructions, ranked items, or any content where order matters.

Blockquotes

Blockquotes add a left border and indentation to set text apart from the main body.

Keyboard shortcut: Cmd/Ctrl + Shift + 9

Blockquotes work well for:

  • Quoting other writers, articles, or sources
  • Highlighting key takeaways or pull quotes
  • Setting apart editorial notes or asides

Code Blocks

Substack supports inline code and code blocks:

Inline Code

For short code references within a sentence, wrap text in backticks. In the editor, there’s no toolbar button — you need to type the backticks manually or paste pre-formatted text.

Code Blocks

For multi-line code, Substack’s editor has a code block option in the toolbar (the <> icon). Code blocks render in a monospace font with a distinct background.

Note that Substack doesn’t support syntax highlighting — all code appears in a single color regardless of the programming language.

Dividers (Horizontal Rules)

Horizontal rules create visual breaks between sections. In Substack’s editor, click the divider option in the ”+” menu that appears between paragraphs.

Dividers are useful for:

  • Separating a header/intro from the main content
  • Breaking between distinct topics within a single post
  • Creating visual breathing room in long posts

Buttons

Substack offers a button block that you can add between paragraphs. Click the ”+” icon and select “Button.”

Buttons are commonly used for:

  • Subscribe CTAs
  • Links to paid content
  • External resource links
  • Product or event links

You can customize button text and the target URL.

What Substack Doesn’t Support

Several formatting features are notably absent from Substack’s editor:

No Tables

As covered extensively elsewhere, Substack doesn’t support native tables. The workaround is to use table images.

No Text Color or Highlighting

You cannot change text color or add background highlighting. This is by design — Substack maintains visual consistency across all publications.

No Custom Fonts

The font is set at the publication level (Substack offers a few font choices in settings) but cannot be changed within individual posts.

No Underline

There’s no underline formatting option. Underlined text on the web traditionally signals a hyperlink, so its absence avoids confusion.

No Superscript or Subscript

Mathematical notation, chemical formulas, and other content requiring superscript or subscript need workarounds (images or Unicode characters).

No Columns or Complex Layouts

Substack enforces a single-column layout. You cannot create side-by-side content, multi-column layouts, or custom grid arrangements.

Workarounds for Missing Features

If you draft in markdown and need formatting that Substack doesn’t support, consider converting your markdown with a tool that handles the gap. DownStack, for example, converts markdown to Substack-ready rich text, automatically handling tables (as hosted images) and ensuring all supported formatting transfers cleanly.

For features like custom colors or complex layouts, the image approach works: design the layout in a tool like Figma or Canva, export as a PNG, and embed it as an image.

Formatting for Email vs. Web

Keep in mind that your post exists in two contexts:

Web: full formatting support, wider viewport, interactive elements work

Email: some formatting may render differently across clients, narrower viewport, no interactive elements

Always use Substack’s email preview to check how your formatting looks in both contexts before publishing. Pay special attention to:

  • Code block width (may cause horizontal scrolling in email)
  • Image sizing on mobile
  • Button rendering across email clients
  • Blockquote styling consistency

Key Takeaways

  • Substack supports H2, H3, bold, italic, strikethrough, links, lists, blockquotes, code blocks, dividers, and buttons
  • Learn the keyboard shortcuts — they significantly speed up formatting
  • Use bold for emphasis, headings for structure, and lists for scannability
  • Substack intentionally omits tables, text color, custom fonts, underline, and complex layouts
  • Strikethrough and some edge-case formatting may not render consistently across all email clients
  • Always preview in both web and email before publishing
  • For missing features, the image workaround (design externally, embed as PNG) is the most reliable approach