I have a way on how you can enter the number, jexim157-gmail-c.
EWay Billis an electronic document generated on the eWay Bill Portal. While automatically showing the Bill No. is not possible, you can either add it on the Message box or add a custom field.
To add a custom field, here's how:
Go to the Gear > Account and settings.
On the left panel, click Sales.
Click the Sales form content section to edit the options.
Enter the name of the custom field and check the Internal box if you don't want customer to see it.
Hit Save and then Done.
Please see this sample screenshot for a visual guide:
For more information about E-Way Bill and custom field, check out these links: