Hello @instantboss,

Great question! 
If you were importing SMS contacts to Klaviyo for SMS consent using either Klaviyo’s API method or a .CSV method, you would not be required to include an email address. This in turn would create phone number only profiles within your Klaviyo account when the import completes. When using the .CSV import method, you can omit the “email” header altogether. 

However, if one of the phone numbers already exists on an email profile (in “proper” format), Klaviyo will pair the uploaded consent to that pre-existing profile. 

You can find more directions and instructions on how to import SMS consent to Klaviyo from the following articles:

• Guide to Uploading a List of SMS Contacts
• Guide to Collecting SMS Consent via API
• Migrating from Another SMS Provider to Klaviyo

Hope this helps!

David