Although you will likely be using multiple software programs and apps to design your tech pack, Adobe Illustrator is a great tool for designing tech packs because it allows you to draw at actual size. This is important because sizing can be tricky when designing since some of the measurements are in inches, centimeters, and pixels. When you draw your designs at actual size using Adobe Illustrator, then there will be no confusion between the sizes.Adobe Illustrator also allows you to easily save your files into a format that most manufacturers will accept (such as PDF or AI). It's easy to accidentally save your file in a format that is unusable by manufacturers if you're using Adobe Photoshop or another program, so make sure you're saving as an Adobe Illustrator file before submitting it.