If you want to share your page with a trusted person you want to give the right to change your page, you need a PRO subscription. Click the Share button and select the option you like.
Instructions
Make sure you are on a personal or team page you want to share. Click the Share button in the header.
Under Invited people start typing an email address.
From the dropdown, you can choose to grant them viewing rights or editing rights.
Hit the plus icon to send the invitation.
You can always change this setting later or remove the invitation altogether.