Open the Facebook app
Go to the post you want to share
Tap the Share button
Select Instagram if the option is available
Choose where to share it on Instagram
Edit the post if needed
Tap Share or Post to publish it
If Instagram is not shown, copy the post content manually
Open the Instagram app
Create a new post, story, or reel
Paste or upload the content
Add captions or tags if needed
Tap Share to publish it