Here we're going to talk about another method, to add tag directly on Audience page
Step 1:
Click「CRM」，go to Contacts page
Step 2:
Move the mouse to the contact you want to tag, you will see a box on the left side of the contact, click to select
Step 3:
After selecting multiple contacts, click the "+" above
Step 4:
At this point, you can click to select the label to add from the list of existing labels, or enter a new label in the input box
Congratulations!👏