You can add an Instagram account to any Facebook Page which you are administrating or editing. Adding an Instagram account to your Page allows you to create Instagram ads in Ads Manager without needing to connect your Instagram account to a Business Manager.
To add an Instagram account to your Facebook Page:
1. Go to your Facebook Page.
2. Click Settings in the top-right of your Page.
3. Choose Instagram from the list on your left.
4. Click Log In.
Now add an existing Instagram account to your Page. To do this еnter your Instagram account’s username, phone number or email and your account password, then click Log In.
That’s it! You have an Instagram account connected to your Facebook Page. From now on, whenever using your Facebook Page to create ads that run on Facebook, you can also use your Instagram account to show those same ads on the platform.