The "bulk edit" function allows you to update tags, automated messages, change consent settings and subscriptions and delete many contacts at once.
Step 1: Select contacts
Select the contacts you want to update. You can select contacts many ways. For example view contacts that belong to a tag, subscription list, view results of a custom segment or click on a drill-down metric in a report.
On the top of the contact list page you will see how many contacts are in your current "view".
Step 2: Click the "Group edit" button
After you clicked the selection checkbox on the top left of the contact list, click the "Group edit" button.
Step 3: Apply changes
Follow the on-screen instructions to apply changes to the selected contacts.