How to Add admin to facebook page

Give Someone a Role

If you're an admin:

Click Settings at the top of your Page.

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Click Page Roles in the left column.

Type a name or email in the box:

• If the person is your Facebook friend, begin typing their name and select them from the list that appears.
• If the person isn't your Facebook friend, type the email address associated with their Facebook account.
• Click Editor  to select a role from the dropdown menu.
• Click Save and enter your password to confirm.

Remove Someone Who Has a Role

If you're an admin:

1. Click Settings at the top of your Page.
2. Click Page Roles in the left column.
3. Click x next to the person you want to remove.
4. Click Save. You may need to enter your password.

To remove yourself, follow the instructions above and click x next to your name. You can always remove yourself from a Page, but if you're the Page's only admin, you'll need to add another admin first.

Change Someone's Role

If you're an admin:

1. Click Settings at the top of your Page
2. Click Page Roles in the left column
3. Click Editor  next to the name of the person whose role you want to change and select a new role from the dropdown menu
4. Click Save and enter your password to confirm

Note: If you are a new admin, keep in mind that you may need to wait 7 days before you can remove or demote another admin.

Credit:https://www.facebook.com/help/187316341316631