In the People module, please follow the steps to assign a Tag to a Person:
1. In People, select one or multiple persons you want to add a Tag, then click on the icon in the top blue bar and select Add Tag.
2. Select the Tag you want to assign.
3. Subsequently you will be able to see the Tags in the 4th column.
If a user is tagged, a new tab called by the tag name is available under the page People.