Please try searching the forums before asking, as we recently covered getting tags out of the metadata cache in this post.
An adapted version of that script for your case is as follows:
```dataviewjs
const tagToCheck = "#Agenda/Fred"
const tFile = app.vault.getAbstractFileByPath(dv.current().file.path)
const tagCount = dv.array(app.metadataCache.getFileCache(tFile).tags)
.where(t => t.tag == tagToCheck ).length
dv.span("There are " + tagCount + " reference(s) to " + tagToCheck)
```
Change the tagToCheck to match your case, and the text of the last line to match your liking.