Depends. How much are you willing to spend? Are you good with productivity software? Blender 3d is free, but difficult to use if you've never used similar software. The most user friendly software I've used is Strata 3d and reasonably priced for about 400 bucks. Google also has free software out there. I think it's called Google sketch. NEVER buy Illusion Mage or 3d Max. They claim to be the best 3d modeling software out there and are indeed cheap, but it's a scam. They're rebranded versions of Blender 3d, which is free so don't fall for that scam. You could download trial versions of Maya 3d and Strata and create your models and export out as images, but there will be a watermark on the rendered images.