How to show validation or disable checkout until the phone number get verified with otp in magento 2?

by |Published January 10, 2020

I am verifying the phone number through OTP in Magento 2 one page checkout. when the user clicks the place order button before the phone number gets verified, I need to show a validation message to verify the phone number.

I have created the OTP verification module for the phone number based on the below link:
How to add custom button under the phone number field in one page checkout in Magento 2?