If you would like to download a LaTeX distribution and front-end/compiler to your laptop, try:
A simple visual editor for writing diagrams and converting it to Tikz github.com/yishn/tikzcd-editor, try it out at https://tikzcd.yichuanshen.de
Math students, connect with prospective employers here: MAA Career Resource Center
Use CamScanner app or another scan app to scan your hand-written homework into PDF.