Is there a way to customize or configure settings for e-bill generation?

Yes, there is a way to configure settings for e-way bill generation in BUSY.
For E-way Bill configuration please follow the below Steps: 
Step 1: You have to create a GSP id (GST Suvidha Provider), you need to visit the eway bill portal. 
Step 2: Click on regisration option then you have to Click on GSP and then send OTP and verify 
Step 3: Create id with Selecting Webtel Electrosoft Private Limited and Pinnacle Finserv Advisors Private Limited as a GSP Vendor type. 
Step 3: Go to Administration and click on configuration. 
Step 4: Select Features / Options and click on GST / VAT, here you will see a option called E-way Required. 
Step 5: Set Y to turn it on and mention your place and pincode, all required and user restrictions also you can define and then clck on GSP configuration Tab then paste GSP username and password and save the configuration which we create from e-way bill portal 
Step 6: Go back to Administration and click on configuration. 
Step 7: Choose the Voucher Series Configuration option and select the voucher type for which you want to generate e invoice, such as sales, sales return, etc. and select series & then click on voucher configuration then enable generate E-invoice after saving and save.