Login to your account at https://squareup.com/us/en and go to your dashboard. On the dashboard, go to Items → Categories. Click on Create a Category. Name your category and click Save. Click on Assign Items and select items that you want to put in the category. Alternatively, you can also assign items to categories through the Edit Item page. Go to https://squareadmin.grubbrr.com/ and click on the Sync Data from Square icon (at the top right corner) to sync your changes.