Why PayPal standard does not have a pay now button?

Hi,

  I am looking to add a payment option to my form.  I put the paypal app in but there is no paypal button, it just says submit form.  Will they need to pay with this option and how will it work?

Yes, the form only needs the submit button and it will redirect the user to PayPal checkout when the user clicks the submit button. Also, if you do not want the form to be submitted if the user does not make a payment or transaction, please set the PayPal field as required. This will prevent your user from submitting the form if they have not selected any items in your PayPal product list.