You can assign as many tags to your products as you like. This helps you to efficiently sort and order your products (for example, to mark certain products for a sales promotion).
Click on "Edit" under your respective product and go to "Tags". Here you type in your tag and confirm with the Enter key. Then click on "Save".
In the bar above your products you will now see that a new tag has been created:
By clicking on the respective tag or using the search bar, you can filter for the assigned products.