Unfortunately I don't believe that Square offers that option with their standard website features. You can submit suggestions to Square for consideration - Square has a Feature Request page setup - if there's enough demand, then it's possible. Another consideration is - it may be possible with the help of a Developer who can write some custom code for your site however, that's a bit beyond the scope of this Community. Square does have a Developer Forum. There are other website hosting services that do have the option to manually approve new orders which would probably be the feature you have in mind. One service is WooCommerce and can work with Square.
