For note taking and sketching I use - exclusively - an iPad Pro 12.9, with the Notability app. Notability has engineering paper as a template, in three colors: sepia yellow, light green, and white.
I can do a quick sketch, then either screen capture a close up or print the whole page as a pdf, and then either drop the captured sketch into a report or print the whole page from the iPad, either way in under a minute if I'm at my desk. I also have a bunch of standardized sketches and hand calculations saved, and a Brother travel thermal printer, so I can work something up right in the field, print it, sign it, and seal it.
I also have AutoCad on my iPad.