I apologize if I am not using the correct name for this program but am wondering where I can find it. I want to try doing a mock-up for a canopy to cover my pool and patio area. Thanks
For a quick, rough mock-up, you can use Microsoft Paint which is an accessory program that should exist on your PC if you have Windows. If you want to get more detailed, then choose one of the more complete programs like the one Sonny Dayz suggested.