Drag to the sidebar
Drag fonts to a tag in the sidebar to attach that tag. When you start dragging the currently attached tags will be highlighted and the sidebar will automatically expand if it has been closed.
If you want to detach a tag instead, hold down the Option key when dropping the fonts. To attach fonts to a new tag you can drag & drop those fonts onto the + button in the sidebar.
Drag to the toolbar
The Typeface toolbar can be configured to be an alternate drop location to attach tags. By default the toolbar will show the multi tagging panel when you drop fonts to the top of the window. This panel allows you to attach multiple tags by typing their names. With fuzzy searching you can rapidly find and attach the tags you want.
The multi tagging panel is very flexible, but sometimes you may prefer to just attach one particular tag instead. This can speed up your workflow when you’re repeatedly attaching the same tag to fonts. And you can keep the sidebar closed to focus on your font previews.
Right click on the toolbar to change the current drop target. You can change it to any tag you want, for example you can use it to quickly mark favorites using a Favorites tag. By setting it to the Quick Collection you’ll be be able to collect fonts and clear the Quick Collection with drag and drop. Or change the target to the Activated tag if you prefer to activate and deactivate fonts.