How to add Facebook account to Instagram
Connecting your Instagram account to your Facebook profile means share content like stories and posts directly from Instagram to Facebook. Keep in mind that you can only connect your profile from the Instagram app for Android or iOS devices.
Connect your Facebook profile in Accounts Center
To link your Instagram account and Facebook profile:
Tap Yes, finish Setup.
Select whether you want to sync your profile photo, then tap Continue.
Once you link accounts, you’ll have the option to share a post to Facebook from the same screen where you add a caption.