What's the difference between an invoice and receipt?

im planning to have my business, but it will be based by mail. I'll provide the SERVICE once they pay me by check, money order or credit card, but do i need to send them a recipt, (carbonless) or an invoice. How can i create these forms?

To put it simply, the invoice is your bill. The receipt is the record of payment that you provide the customer.

If you customer wants to know what he is paying for he should be able to read the invoice which will have all the information about the transaction including quantity and description of the goods or service, price, additional charges including shipping and taxes, the total price and the payment terms.

The receipt should show date of payment, method of payment, amount of payment and a reference to the invoice the payment relates to. It should also show any balance still due.

An invoice will show the nature of the service that you provided and details of the price that you are charging.
e.g. To supplying one copy of "War and Peace" in good condition, with charge for packing, insurance and postage + tax.
There are two charges here: one for the book and one for the other parts of the service. The prices will be listed separately and, if necessary, the tax will be added finally.
A receipt will show the amount of money you have received and when you received it. You could add the form in which the money arrived with you: check, credit card, etc..
Best wishes in your enterprise.