When you add your Instagram account to the same Accounts Center as your Facebook account, you can easily share content such as stories and posts directly from Instagram to Facebook. You have the option to link multiple accounts to a single Facebook profile.
To add your Instagram or Facebook account to an Accounts Center:
Tap on your profile or your profile picture in the bottom right to go to your profile.
Tap on "more options" in the top right corner, then tap on "Settings and Privacy."
Scroll to the bottom and tap on "Accounts Center."
Tap "Add Facebook account" or "Add Instagram account" and follow the on-screen instructions.
Once you've added your accounts to the same Accounts Center, you'll find the option to share a post to Facebook on the same screen where you add a caption.
To remove your Instagram or Facebook account from an Accounts Center:
Tap on your profile or your profile picture in the bottom right to go to your profile.
Tap on "more options" in the top right corner, then tap on "Settings and Privacy."
Scroll to the bottom and tap on "Accounts Center."
Tap on "Accounts."
Tap "Remove" next to the profile you'd like to remove.
Tap "Continue," then tap "Remove."
I hope this helps! If you have any more text that needs translation or any other questions, feel free to ask.