Hi Lana,
To perform SMS or OTP verification prior to form submission, you can utilize the “miniOrange OTP Verification Add-on” provided below.
It also offers the following:
- Verify User’s Identity Before Form Submission
- Mobile Verification
- Email Verification
- SMS Notification On Form Submission
- Send Notification To Admins And Users
Please follow the setup guide below. 
Give it a try, and let me know how that goes! 