Figures submitted with a provisional application can be informal.  A figure can be a hand drawing, a photograph, a CAD illustration, VISIO files, flow charts, block diagrams, or any other type of visualization of your invention.  They do not need to contain labels or be referenced to the description portion of your Provisional Patent, though it is best to do so.  If you can, SmartUp® asks that you convert your figures into PDF format prior to uploading.

If you are interested in more detail related to your situation it is best to speak with an attorney.

Yuri Eliezer heads the intellectual property practice group at Founders Legal. As an entrepreneur who saw the importance of early-stage patent protection, Yuri founded SmartUp®. Clients he has served include Microsoft, Cisco, Cox, AT&T, General Electric, the Georgia Institute of Technology, and Coca-Cola.

Source: Smartup Legal