This functionality will be included with Release 72.0 and beyond.
It is possible to set validation rules for phone number inputs in both the legacy Single Page Checkout and Customer Table components.
To set validation on the newer Modular Checkout, go to Form subcomponent: Field.
Steps to set the phone number validation:
1: Click on the profile icon in the top-right corner of the app.
2: Click on the Developer option in the dropdown.
3: Click General Settings, then Localisation and type the regex code you wish to use in the Regex for phone number validation input.
Note: regular expressions (regex) are patterns used to match character combinations in strings. They must be entered here without being enclosed between slashes.
4: Don't forget to save the changes by clicking the Save button in the top-right of the page.
The phone number input on the Single Page Checkout and Customer Table must match the regular expression (regex) specified here in order to pass the validation that allows the forms to submit.