Add Global Tag

Select the tab Tags from the bottom. Then click the plus ( + ) button from the top left toolbar to add a global tag. Fill in the tag name then click Finish.

Add Tag To Operation

Select the tab Paths from the bottom. Select the operation you want to add the tag to. Select the tab Tags from the right view then click the + button.

Fill in the tag name, then click Finish.

Please note that you can directly make this new tag a global one by checking the check-box