Hey, I see you require 3 forms completed for your WordPress website. I hope for the Vendor registration form requiring an OTP verification, you have a SMS provider finalised as based on which I'll be able to help you with OTP further.
I am online at the moment so feel free to initiate a chat and discuss further. I am a new freelancer here, but have an experience of more than 2+ years working with WordPress websites. Happy to walk you through my best works over call or chat.
Thanks for taking the time to read my proposal! Happy Coding!