There are three ways you can apply a tag to a contact:
Tags can be applied as you are creating a new contact. Enter one or more letters to view any matching existing tags. If the tag you are after doesn't exist, continue typing to create and apply a new tag.
Once the contact is created, the applied tags are visible on the Contacts screen.
Import a Contact
When importing a new contact, a column is provided to add tags to each contact. Enter all tags for each contact in the Tags column, separating each tag with a comma.
Tags can also be applied or removed to existing properties from the Contact Details screen.