Tags are the small one-word or phrasal descriptions added to any product, which help you categorize and organize them. Any user in Magento, once logged in, can add, rename, or delete as many tags to their products as they want. They are visible as blocks on the front end, to anyone viewing the product, and would also reflect in the product info page.
Firstly you need to login to your Magento admin and go to your Magento control panel.
Click on Catalog>Tags>All tags.
Click on Add New Tag at the upper right-hand corner.
Key in the preferred Tag Name, and make sure the Status is set to Approved.
Click on Save Tag.
Once you’ve created your tag, you can select the products to be associated with your tag, by following these steps:
Click on the created tag and expand the products that have been tagged by administrators already.
Reset the filter and select the products that you want to be listed under the tag.
Click on save