In order to post on your Facebook Business page, someone who is an ADMIN or OWNER of the page must do the following:
If you're an admin:
- From your News Feed, click Pages in the left menu. You may have to click See More first.
- Go to your Page and click Settings in the left menu.
- Click Page Roles.
- Below Assign a new Page role, type a name or email in the box and select the person from the list that appears.
- Click Editor and select a role from the dropdown menu.
- Click Add and enter your password to confirm.
Keep in mind that if you're not friends with the person you're adding, they'll have to accept your invite before they can start helping you manage your Page.
Remove Someone Who Has a Role