Only Superusers can do this.
You have the ability to change the values of multiple members simultaneously without needing to edit each member separately. For example, you can quickly assign multiple members to the same billing group.
In the side menu click Org Tools > Accounts.
If you want to edit a subset,
Click Customize Filters...
Click the dropdown you want to filter, such as Member Groups, then select which elements you want to include.
You can do this with multiple criteria.
Select one, many, or all in the member database.
Click Edit > Multi-Edit.
Place a checkmark to the left of one or many options.
Select the new data.