Go to group profile which want to join or find group from explore list also.
Click on Join button to join the group, or find Join Group button (for Closed Group) at top of the Wall tab to join the group.
User can join automatically or can send a join request to admin of the group.
In join request, after admin approve that request can join in that Group.
Before accept the request join button shown as Pending. And can cancel the request on click pending, then a option show as Cancel Request. Also a Cancel Request button shown in wall tab to cancel the request.
APP :
Find group profile from left drawer explore list, or go to group profile.
Click on Join button to join the group, or Join Group button (for Closed Group) at the top of the Wall tab to join the group.
User can join automatically or can send a join request to admin of the group.
In join request, after admin approve that request can join in that Group.
Before accept the request join button shown as Pending. Can cancel the request on click pending, then a option show as Cancel Request. Also a Cancel Request button shown in wall tab to cancel the request.