If you’ve been added to a Facebook group and you want to leave the group, you can follow the steps below to remove yourself if you’re using Facebook on your mobile phone.
==> Sign in to your Facebook account via m.facebook.com
==> Navigate to the group
==> Tap the “info” tab
==> Scroll down and tap “Leave group”
==> Select “Prevent users from re-adding me to the group”
If redirected back to the group, you should now see “Join group” button.
Repeat same for all those annoying groups you’ve been added to.
If you would like to remove yourself from many groups at once, read how to leave a group on Facebook.