My datasets are in a paired collection. But there isn’t any tag icons. See the bellow image. How can I tag my datasets?
If you want to tag the collection itself, click on the pencil icon for the collection. That icon is in your screenshot: top right next to the collection name.
To tag the datasets (files) inside the collection (folder), please see these tutorials. https://training.galaxyproject.org/training-material/search2?query=tags
And there was recent Q&A about this in another post by someone else. Might help more if you have trouble: Collection Operations: Tag elements