Convert Mac Excel Spreadsheet into Numbers on Mac Pro Air

If you want to print labels then Numbers may not be your best choice. It will probably a lot easier to import your address data into the Contacts app (via CSV) and print labels from the Contacts app.

Import contacts into Contacts on Mac - Apple Support (IN)

Print mailing labels, envelopes, and contact lists in Contacts on Mac - Apple Support (NG)

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You can directly open the Excel file in Numbers from the File Menu.

Link-> Import an Excel or text file into Numbers on Mac - Apple Support