Remove plugin

Click on the Plugins menu option in the WordPress Dashboard.This will list all the plugins available on your site. Deactivate the plugin you no longer need then once it’s deactivated, you can also Delete it if you dont think you’ll be requiring it anymore.

But roles and capabilites automatically return to wordpress original? I change name of roles, what will appen if i deactivate without any operation before?

I’d suggest editing each user Profile (User menu) and setting them back to one of the default WordPress users and then deactivate and remove the plugin. You can see what the default roles are, here…
https://codex.www.ads-software.com/Roles_and_Capabilities#Summary_of_Roles