You can use word processing software like Microsoft Word to create documents or you can write the Postscript code that your printer requires to print documents. Both can produce nice documents but it is much more difficult to write Postscript.

I learned enough of OpenScad to create simple models but if I need something complex (and especially models that move), I used Fusion 360. I knew that it would cost $60 a month to me at some point and will need to evaluate if it is worth that much to me. While it's not pleasant to get something for free and then have to pay for it, it's not the first time it's happened and won't be the last.