Markdown is a way to add structure to plain text using characters you can see and type. Write # before a title, - before a list item, or ** around a word you want to emphasize. The text stays readable before any app turns it into a formatted view.
Here is the same thought in source form:
# Trip notes
Pack the **small notebook**.
- Train tickets
- Address of the hotel
A Markdown viewer can show a large heading, bold words, and a list. A plain text editor shows the marks. Both are views of the same writing. Try the live preview and switch back to the source to see the relationship yourself.
What problem does it solve?
Formatting a short note should not require a toolbar or a particular app. Markdown gives you a few conventions that are quick to type and recognizable later. It works well for notes, README files, drafts, documentation, and messages where the content matters more than exact page layout.
Markdown began as a writing format for the web. John Gruber's original syntax description explains the readable-text idea. The later CommonMark specification makes many core parsing rules precise. The two are related, but "Markdown" is still used broadly for several compatible and extended flavors.
The three things people call Markdown
The syntax is the set of marks: # for headings, * for emphasis, brackets for links, and so on. The syntax guide is a compact reference.
The file is usually plain text saved with a .md or .markdown extension. You can open it in a basic editor and inspect the actual words. The extension does not magically contain images or guarantee that all links will survive a move. The file guide covers those details.
The rendered view is what a particular app or website makes from that text. Two apps can show the same core headings and lists but disagree about extensions such as tables, task lists, callouts, or wiki links. A note can be written in Markdown even when an app stores it in a database instead of a separate .md file.
A few marks are enough to begin
Write a heading with # Heading. Start a list with - Item. Make a link with [label](https://example.com). Surround a phrase with ** for bold or one * for italic. Leave a blank line between paragraphs. You can learn more when a real note calls for it; there is no need to memorize the whole reference first.
When you share text with someone, ask what their destination supports. GitHub, a notes app, and a publishing system may interpret an extension differently. Our CommonMark guide explains where the shared core ends.
When should you choose something else?
Markdown is a poor substitute for precise visual layout, tracked edits in a team document, or a spreadsheet. It cannot ensure a recipient sees the same typography you do. A rich text document can be a better choice when the final appearance or visual collaboration is central. The format comparison is meant to help with that decision, not declare a winner.
If you want to keep personal notes in Markdown, start with what Markdown notes are. That guide moves from syntax to storage, sync, and long-term access.