In the form builder app, you will have an option to create customer on your approval. Follow the below instruction to setup approve/deny option for every submission on your store.

Instruction –

1. Go to the app and click settings.

2. Enable approve/deny option as per your requirement.

3. Go to the app dashboard and click the submission list.

4. You can approve or deny customer submission from this section and you can create a customer in Shopify customer section after approving submission from the submission list.

{Note: Approval & Deny email is only available on a registration form and wholesale form, else in other forms you will receive submission normally in your apps submission list.}