How can I remove the billing phone number from checkout, or at least make it not required?
I've looked everywhere and can't find any references to the form.
After facing the same problem, i found a thread on the official git. Dated from August 2015...
And someone posted a proper solution
Incredible complexity for just doing that...
I'm not sure about previous versions but in Magento 2.2 you can go to
Store > Configuration > CUSTOMERS > Customer Configuration
Then go to the Name and Address Options tab on the right and look for Show Telephone and select your option. (No) (Optional) (Required)
It's set to Required by default.
You can make it not required for only billing address by run bellow query to database.
update eav_attribute set is_required=0 where attribute_code='telephone';