Obsidian Metadata can be added by adding a frontmatter section at the first line of the markdown document. Out of the box, Obsidian only supports the following metadata tags:
| Key | Description |
|---|---|
tag |
Adds a tag to a note. |
tags |
Alias for tag. |
alias |
Adds an alias to a note. |
aliases |
Alias for alias. |
cssclass |
Allows for a custom style on individual notes using CSS snippets. |
Source: help.obsidian.md