Exit or uninstal Avast

I try uninstal avast, but not have enough privilege nor I can’t exit from avast. How can I do this procedure?

Thank you

What is your OS ?

If you aren’t running from an account with admin privileges then you can’t uninstall, the same is true to install it.

So who installed it ?
Are you using a user account with enough privileges, e.g. admin group ?

Does the Stop On-Access Protection (right click on the avast ‘a’ icon) option not work ?

Why do you need to uninstall or exit from avast ?