To unlink your Instagram account and stop sharing your Instagram posts to another social network such as Facebook:
Tap

or your profile picture in the bottom right to go to your profile.
Tap

in the top right, then tap
Settings and privacy.
- Tap Account.
- Tap Sharing to Other Apps, then tap the social network you'd like to unlink.
- Tap Unlink Account (iOS) or Unlink (Android).
- Tap Yes, I'm sure.
If you're trying to relink Instagram to a social network, you may have to visit that social network’s app settings or preferences to unlink your previous account.