The Batch Update tool allows you to edit multiple records at the same time.
Select records as you normally would, and click Batch Update.
You can keep this selection set, or use new selection tools to create a new selection set.
You have the option of keeping the existing values for a field, or setting the fields for all selected records to be a designated value. Choose Save to apply the edits.
Note that for the Batch Editing function to appear, only one selectable layer (if applicable) from the Choose Selectable Layers drop-down menu can be checked.