Only the creator of the post can edit a post. The post creators will see the menu icon for all the posts except system-generated posts.
When a user chooses to edit a post:
It will take you to the post edit flow which is the same as the post creation flow with the images, attachments, and written content pre-filled.
You will be able to edit who can see this post.
Edited posts when saved, will contain an 'edited' label - a few seconds ago, X minutes ago, X hours ago, X days ago, etc.
Only the creator of the post can delete a post by clicking on the menu icon. When a user chooses to delete a post:
The creator will receive a confirmation pop up 'Are you sure you want to delete this post?'
You can then choose to confirm or cancel the deletion.