You can edit your own posts to update the caption or tags.
Steps:
Find the post you want to edit.
Tap the ••• icon on your post.
Select Edit.
Make your changes, then tap the checkmark in the top right to save.
Good to know:
You cannot replace images or videos after posting — only the caption and tags can be edited.
If you need to change the media, delete the post and create a new one.
All edits must comply with our Community Guidelines.