Adding or changing a Shopify product's tag is trivial using Airtable. First, create a "Tags" column in the Airtable sheet where product information is being synced to. This can either be a text column (where you enter tags separated by a comma) or a link to a special "Tags" sheet (the option we recommend). If you need help to do this please reach out to the BaseGenius team!
After you've set up the Tags column, add new tags to whichever products you want. When you are done, simply start the Airtable to Shopify sync and the Shopify products will be updated with the tags you've specified for them in Airtable.