If you want to better control over which Pages can tag you in future branded content, turn on Page Approvals.
To tag products when creating a post: Upload your photo or video post. In a photo, click the product you want to tag and type in the product's name. Before you begin, make sure you have products in your Facebook Page shop. ; You can view your list of blocked Pages in the Branded Content tab of your Page Settings.You can block up to 10 Pages at any given time. Click the Tag Products icon. You can tag products while creating a post or tag products in an existing post.
Click Confirm in the remove tag confirmation screen.