As a stakeholder, you can add process tags from within a process.
Quick Steps
Open the process or value stream
Select 'Edit Information' at the top of the map
On the details tab, scroll down until you find Tags
Click on the box beneath it to see a list of all existing process tags
Select the desired tag or create a new one by typing the new tag in the box and pressing 'enter' or 'tab'. The new tag will appear in the box
Select the green 'Update Process' button at the bottom of the card
Edit or delete process tags via the Object Tags settings page.