You can use the "Bulk Tagging" action on the Members List. You must select the members of the page by clicking on the checkbox to the left of their name then at the top right of your screen, click on Bulk Actions > Tag. Then add or create the associated tag.
If you want to tag a long list of members, please send an Excel file to your Customer Success Manager with all the email addresses of the people to tag and the name of the tag to add.
On the Comments List, you can filter your comments in two ways: