If I remember correct, could be wrong as I don’t use google, the latest version of OH will allow you to create tags via PaperUI. Try searching the forum for “PaperUI tags” to verify.
If this is not available or your using OH 2.3 or older and do not want to update then create the item in your items file. This file for Linux is located at etc/openhab2/items and add the tag like.