Software to help with spec design sheets

Hello All,
I’m wondering if anyone can help me? I’m starting up my own clothing line soon and have already have lots of ideas so far. My problem is creating the specification sheets for the manufacturers. I can sew but I’m not very good with measurements or pattern grading etc. I’m thinking about purchasing software to help me with this. Does anyone have any names or recommendations of software packages to help me with patterns/measurements and the garment specifications? I have googled fashion software but im wondering what they are like?
Many Thanks,
Peekaboo