You can edit or delete posts or comments you have posted in a group, but you cannot delete another member's posts or comments. Posts or comments by other members can only be deleted by group owners or administrators. If you delete a post or comment, all likes, reactions, and comments will also be removed.
How to edit or remove a post or comment from a group:
Click the three dots icon in the upper right corner of the post or comment. Click on the icon to perform the desired action.