Boom, the new phone rule feature is here! 💥☎️
These rules will ensure the phone number entered in the shipping section is in the correct format based on the country. For example, you can enforce the format of US phone numbers to be 9 digits long and not worry about getting incorrect info!
A prerequisite to this is having a Shopify Plus subscription (which is unfortunate, but is a platform limitation). To start using it, you need to go to the Phone Validation section, where you'll see something similar to the Postal Code Rules section:
Now, as you can see on the screenshot, all you need to do to add a phone number rule is select one of the supported countries on the dropdown list, the number of formats you're going to be allowing for that country as well as the warning message that will be displayed, and lastly -- the structure of that format. For example:
Click on the Add button, and voila, you have your phone number rule in place!📲