What is a one-sentence summary of the following article?
Whether you make an invoice on the computer or use an invoice book, write the name of your company at the top. Include the following information about your company just below the company name:  The complete address The phone number The email or any other pertinent contact information It's always important to you and your clients to know the date of the invoice. That's because payment is usually due within a certain number of days of the date on the invoice. You'll number the invoice sequentially according to how many transactions you've had with the client. For example, if you've sold cakes to the same client on three different occasions, the invoice for the third sale should be #3.  If you're using invoice slips that you purchased at an office supply store, the invoices will already be numbered. If you're using accounting software or PayPal, the invoice will also be automatically numbered. Include the customer or client's name or company name. If you performed services for the client as a contractor, you should also include the company address and phone number.

Summary:
Include your company's information. Provide the date. Number the invoice, if necessary. Write the client's information.