I have an online service for which customer subscribes and pays a monthly fee. They use Paypal or Google Wallet to make these payments. Customers are starting to ask for invoices. Is there a way for Paypal or Google Wallet to generate these invoices? Do I have to manually generate these invoices for customer (and if so, what is the standard template for invoices)?
I don't have any experience with Google Wallet, but Paypal has invoices, yes. You can invoice customers manually, but that probably wouldn't work too well with your by-the-month billing. One option is to use their invoicing API, which will generate the invoices programmatically.