This is the guide from me. To merge your Pages:
1.In the top right of Facebook, tap .
3.Go to your Page and tap More in the top right.
4.Tap Settings then tap General.
5.Tap Merge Pages and enter your Facebook password, then tap Continue.
6.Tap Choose a Page to select 2 Pages you want to merge and tap Continue.
7.Tap Request Merge.
If you're unable to merge your Pages, it means that your Pages aren't eligible to be merged. If you see the option to request to merge your Pages, we'll review your request.
Note: If your Pages are on Business Manager, you can go to business.facebook.com/pages/merge to merge them.