What software could I use? I only have the new iPad and no pencil….no pc.

[airscapes]

Take a look at at onshape.com. Free but anything you make is available to other users to use. It is all online so only storage needed is to download the stl file. It is a full blown CAD system and takes some work but the very basics will not take long. After a few years as hobbyist I can now spin up what I need in less than an hour most of the time unless what I am doing forces me to learn something new about onshape.. .. The online documentation is much better now then it was when I started with it as it is relatively new in comparison to Solidworks. Last week I wanted a bit holder for one of my cordless dills.. so I made one using TPU filament, also made a 2 bit version and one with imbedded magnets to hold long extensions ..