You can edit multiple contracts simultaneously on the Contracts Dashboard page using the Bulk Actions drop-down menu in the top right corner.
If you want to know more about the other two options, see Contracts Bulk Adding/Updating/Removing People
Bulk Edit Contracts Window
You will be able to edit only the Attributes that are shared among the selected Contracts. Adjustable contract fields cannot be bulk edited as these have to do with terms and not the overall contract. This includes the Start Date, End Date, and Value fields.
Once you select the Edit Contracts option, the Contracts selected can be seen in the Show/Hide button.
To edit attributes to several contracts at once, select the checkboxes next to the Attributes you would like to edit: