There's no default category on the profile for notes, but this can be easily set up!
In order to create this category, head to:
- Settings
- Data management
- People’s data fields
- Add new category
- Add new table
This is how I have my Notes category set up:

And this is how it looks like on the profile:


Just don't forget to turn this category visibility off on the Permissions groups "All people - other’s data" and "All people - own data", if you want this category to be private (this is commonly used for HR notes for example)! 🙂️