How to import groups of contact and make it a new group
You can import contacts and assign them to a group as you are importing. See https://docs.civicrm.org/user/en/latest/common-workflows/importing-data-into-civicrm/#preparing-to-import-data
When creating the Group check the box for &quot;Mailing List&quot; otherwise it won't be available as a group when you go to CiviMail - New Mailing.