Hello @HenrietteR ,
If it's a default field (first name, last name, etc.), then it wouldn't really be able to be deleted, but custom fields can be.
If you are particularly wanting to clear out and consolidate those particular fields, then it may be best to export your contacts, and work to get the multiple columns condensed using your preferred spreadsheet program. However, you'd then need to delete all your existing contacts so when you re-import, you only have the one phone number column. Keep in mind, that this means you'd need to rebuild and reassign contacts to individual lists as well, so I'd only recommend going through this process if you're really wanting to consolidate the phone numbers.
... View more
