If the options "Available in filter" and "Available in list" are selected for a custom field, it becomes available for to use as a filter in the order and customer list tables.
Bulk operations for custom fields
You can also make bulk changes to the value of custom fields in in the order and customer cards.
Note that to make these bulk changes, the fields must be editable.
Note
You can edit up to a maximum of 100 custom field values for orders or customers at any one time.
To change the fields, select the desired customers/orders from the list and click on the "Action" button. Next, hover over the "Change custom field" option and select the required field.
When you click on the field name, a window will open where you need to enter a new value and click the "Send" button.