One of my client had a requirement that the quotation form should have a serial number as the first column. Quickbooks does not have a default feature of adding a serial number in the datagrid. The way to accomplish is to customize the form. To customize the form click the Customize on the top right in the quotation form. Click on additional customization. Click the columns and add a new column named Sl.No. And put a tick on the form and print checkbox. The only downside is that you have to manually enter the serial numbers. In this way you can customize the forms and add some columns that you need according to your company. Its a very useful if you really need some good customization.