I use woocommmerce to sell online courses in my website. also I use a plugin called “Digits” to help users easily login/register using only their mobile phone numbers and OTP sent to them as sms.
So the login/register in our website, just requires entering mobile phone number.
and because of that, we removed billing_phone field from woocommerce checkout form because every user is required to register with their phone number even before accessing the checkout page.
the question is : how to automatically add the “digits” phone number to woocommerce billing_phone filed in every order using maybe some filters and/or hooks?