To add a Facebook business administrator using Graph API Explorer, please follow the below steps:
- Go to the Graph API Explorer in the Facebook Developers website.
- Select the relevant application from the drop-down menu on the top right of the page.
- Click on "Get User Access Token" button and select the "manage_pages" permission.
- Generate the access token.
- In the search bar, type the page ID for the Facebook business page you want to add an administrator to.
- Click on the "Submit" button.
- Click on the "Add a person" button in the "Admins" section of the page.
- Enter the email address of the person you want to add as an administrator.
- Select the role you want to assign them.
- Click on the "Save" button.
The person you added will receive a notification that they have been added as an administrator for the page. They will need to accept the invitation to become an administrator.