You can restrict access to your public page by requiring visitors to enter a password before viewing it. This is a simple way to keep your content private while still sharing it with selected users.
Navigate to settings page
Go to Settings → Page → Privacy
Select privacy option
In the Page visibility dropdown, select Password Protected
Enter your password
Under Password, enter a password of your choice
Anyone visiting your page will need to enter this password to gain access.
You’ll need to share this password with others, so be sure not to use anything
sensitive to you.