In Copilot, you can bulk add tags to your customers.
To do this, you will want to start by going to the Customers tab. Once you are there you will want to filter by all of the customers that you want to receive the tag.
Once you have filtered your customers, you will want to select them, and click the Add Tags button at the top of the list. Here you can search for the tag you would like to add, and click Save Tags.