How to bill client/write up invoice

I just got into a side project of doing some quick architectural renderings. There are a lot of them, and we negotiated a price based on a per image basis. He had left the billing up to me (as far as how often and what not). However, I do not know what requirements there are for invoices? Are there certain things that should be included? Is thee a format that I should follow in order to make it easiest for the client to understand? How do all you freelancers do it? Also, am I going to have to do anything as far as taxes go (possibly register as a business?)

As you guys can tell, Im in pretty open territory here. I just want to be sure that I am doing everything correctly, as this may lead to a lot more side jobs.

Definitely get a tax ID. In most states it is easy to register as a sole proprietorship and usually not expensive. Set aside a portion of your earnings for tax time based on your annual salary.

as far as the invoice, I just have a simple header with my contact info and the client’s contact info, then a simple chart bellow showing the incept and completion dates of the project, the project title, and then multiple lines to itemize what was done and the fee for each phase. A total amount due box caps it off at the bottom.

Be sure to include payment terms like how long they have to pay you. Some say “payment due upon receipt” or “due immediately.” Others give NET 10, 15, 30 days which means you are giving them a set number of days to make payment. Of course for you the sooner they pay the better. Some add a penalty like “Late payments subject to 1.5% interest per month penalty.”

You should definitly register as a business if it is anything more than beer money (and even you should register).

It depends on relationship and what the size of the company is for what they want. Name, address etc plus what it is for is required. May want to think of invoice numbering

Personally i would use a online billing service like this
http://www.creativeprooffice.com/
It makes it much easier to keep track of what you are owed and when its due. Client and you will find this very useful espeicaly if you are doing lots of work.

Sometimes there is a field for a Purchase Order or PO number provided by the client, helps the client know which project it’s for.