Payment authorization only

I've registered with Stripe

How can I tell if paments entered on the form would be for authorization only

If you don't want to charge the customers when the form is submitted, you have to set CHARGE CUSTOMER IMMEDIATELY OPTION to NO inside of the Stripe integration. This literally means your customers will never be charged immediately after submitting the form. You will be able to charge your customers later from your Stripe account. 

For more details, please check this guide:

How to Enable Payment Authorization