Obsidian Flavored Markdown adds a syntax option for adding Obsidian Callouts, which are nicely-formatted blocks that can be added to notes.

To make a callout, use the following code:

> [!note]
> 
> Hello World!

This renders:

Note

Hello World!

note can be replaced with some other callout type. Obsidian provides the following out of the box: abstract, summary, tldr, info, todo, tip, hint, important, success, check, done, question, help, faq, warning, caution, attention, failure, fail, missing, danger, error, bug, example, quote, and cite.

Source: help.obsidian.md