Before connecting an Instagram Account to a Facebook Page, be sure of the following:
The Facebook Page to be connected is public.
The Instagram Account to be connected is a Creator or Business Account.
The email address connected to Facebook and Instagram is the same, up to-date email that is checked regularly.
To connect a public Facebook Page to a Business or Creator Instagram Account, complete the following steps.
Step 1:
Login to Facebook and from the News Feed, select "Pages".
Step 2:
Select the desired Facebook Page, then select "Page Settings".
Step 3:
Select, "Instagram" in the left column, then select "Connect Account".
Step 4:
Toggle "Allow access to Instagram messages in Inbox" on, then select "Continue".
toggle this on to allow people who manage your page access to view and respond to Instagram messages.
Step 5:
Enter the username and password for the desired business/creator account, then select "Log In".
Step 6:
Once the two are linked, the Instagram Settings Page on Facebook will appear.
For help creating a public Facebook Page, head here.
Learn how to switch Instagram Accounts into Business/Creator Accounts here.