DO I ALWAYS HAVE TO APPROVE SUBMISSIONS

I am not sure if I have understood your question correctly.

Do you mean to say that your payment submissions ended up in "Incomplete Submissions"? Please note that when users submit your form, they are redirected to PayPal checkout page for payments. If your user do not settle the payment, that submission is marked as "Incomplete Payments".

I would suggest you to please take a look at the following guide for more information on incomplete payments:  https://www.jotform.com/help/272-Paypal-Incomplete-Payments-FAQ 

Have you received these payments in your PayPal account?

If you do not see the payments in your PayPal account, that means your users have not completed the payments when they were redirected to Paypal checkout page. 

If you have received the payments in your PayPal account that means the IPN of your PayPal account is disabled. I would suggest you to please enable IPN of your PayPal account and that should solve your problem. The following guide should help you:  https://www.jotform.com/help/276-How-to-Enable-IPN-on-your-Paypal-Account 

I would suggest you to please explain your question a bit more in detail and we will surely help you.