Add a new tag to multiple contacts

To add a new tag to about 100 contacts, do I need to go into each individual person to add the tag or is there an easy way to do it?
-Mary

The easiest way to do this is by exporting your contacts into a CSV (Settings > Import / Export) and and segmenting the 100 that you want. The re-uploading them using Settings > Import / Export > Import Email Addresses. Here you can upload the spreadsheet again using the new tag, these contact will not be duplicated but will be tagged appropriately.