If users created a Custom field for Work Orders and this field is not showing any value when pulled up from the Inventory Back Order Report, kindly check the setup of the Custom field and make sure of the following:
1. Using an Administrator role, navigate to Setup > Customization > Transaction Body Fields.
2. Click on the field name.
3. Store Value = True/Checked
4. On the Applies To tab > Sale checkbox = True/Checked and Work Order / Assembly Build checkbox = True/Checked
5. Click the Apply to Forms button.
6. Make sure it is only applied to Work Order / Assembly Build Forms.
7. Click on Save.
To add the Custom field on the Inventory Back Order Report:
1. Navigate to Reports > Inventory/Items > Inventory Back Order Report > Customize.
2. On the Edit Columns section > Add Fields > Order Items Pending Fulfillment folder > select the Custom field.
3. Rename the report.
4. Click on Save.