Custom Avatar Support

Hello :D.

I am currently developing a theme which can be seen here:
https://oqueuefansitedev.co.nf/

And i want my users to be able to upload a custom avatar for use on the forums / posts / whatever.

I know there are alot of plugins out there that accomplish this, but i’m trying to avoid using plugins whenever possible.

Is there a wp_theme_support() or anything like that i can include in my functions.php to accomplish this?

Or a way to do this without using a plugin?

Thanks! ??