Method Community

First, When I create a new Invoice with InvoiceLine the Rate is set as 0.0 although I set a value on it !  this is the body ...

Hi there, I connect method:crm with Quickbooks and use method:crm API in my php project but I don't know what the fields I can send for each table, can anyone help me? And are there any way to send an email of the invoice to the customer using the API?