Here is use a document camera to illustrate how you can use Tinkercad on the iPad.
Document camera used is the IPEVO VZ-R - https://www.ipevo.com/products/vz-r
TinkerCAD can be found here - https://www.tinkercad.com/
CREDIT: Subscribe Button by MrNumber112 https://youtu.be/Fps5vWgKdl0