Open a Markdown file in Files to read or edit it. Select New file to create a document. Rich editing requires edit access and supported document size and syntax; files remain stored as Markdown.
Formatting text
Select text to open the formatting toolbar for bold, italic, strikethrough, inline code, and links. You can also type Markdown, such as **bold** and *italic*. A link's hover card lets you open, copy, edit, or remove it.
| Action | Shortcut or Markdown |
|---|---|
| Bold | Cmd/Ctrl + B |
| Italic | Cmd/Ctrl + I |
| Link selected text | Cmd/Ctrl + K |
| Heading | # through ###### |
| Blockquote | > |
| Divider | --- |
Bullet, numbered, and nested lists are supported. Task lists have checkboxes you can tick in the document when editing is allowed.
Insert blocks
Type / at the start of a block or after whitespace to open the insertion menu. Choose a heading, list, table, code block, image, or another available block. The menu does not open inside tables, code blocks, inline code, or links.
Tables
Insert a table from the slash menu. Select a cell to open the table toolbar, then add or remove rows and columns, or delete the table. The header row stays in place; you can edit its text. Column resizing and merged cells are not supported.
Code blocks
Fenced code blocks have syntax highlighting and a language picker. Choose mermaid to render a diagram. Select Show source when you need to edit its definition.
Images
Paste or drag an image into the document, or insert one from the slash menu. Drag a corner to resize it. Uploaded images are stored as files and referenced from the Markdown document.
Markdown fidelity
Rich editing can normalize Markdown syntax, such as changing _italic_ to *italic* or a setext heading to a # heading. It does not promise byte-for-byte preservation of the entire document.
YAML frontmatter is kept separately and restored when the document is saved. Footnotes, HTML comments, and raw HTML constructs retain their source text. Preserving that source does not mean every HTML construct renders as a visual editing control.
If a document cannot safely round-trip through rich editing, it opens with a read-only rich preview and an Edit source action for members with edit access. Examples include hard line breaks inside headings, non-canonical HTML entities such as ©, and some reference or image constructs.
Rich editing supports up to 262,144 characters. Edit source can open text files up to 50 MiB, but saving sends the entire content in a JSON request capped at 10 MiB, including encoding and escaping. Download or process files elsewhere when these limits prevent editing.
A file may also be temporarily read-only while Sim is writing it or the collaborative editor is connecting.
Download a document
Select Download in the viewer. For an open Markdown document, the download can use the visible snapshot without saving it or advancing the collaborative file. Downloading a snapshot is separate from saving changes to the workspace.
When a Markdown export includes eligible stored images, Sim downloads a ZIP containing the document and an assets/ folder, with image references rewritten to those assets. An export without bundled assets is a Markdown file. Missing or oversized assets can retain their original links, so check the exported document before sharing it elsewhere.