I am also a service provider and for my billing requirements I am using KYG-Invoicing.
This billing application is coded by me and I have made it available to public for generating GST compliant tax invoices.
You can use this application to:
- Create master database of your clients, products
- Generate Tax invoices
- Book receipts to track each invoice
- Generate reports to file GST returns
As I am using this application for my own billing requirements, I make sure that it is updated regularly to comply with requirements of GST law.
My intention is not to spend much time in return filing, so I have worked on data formats required to GST return filing.
You can use this application and let me know if you are looking for any specific requirement.
It is a community driven project and is completely free to use.