The Microsoft Equation Editor allows for creating very professional-looking math explanations and proofs in all MS Office Suite products. If you’re used to submitting complex math by hand, I strongly recommend learning the MS Equation Editor to type your assignment submissions instead. It is much easier than it seems at first, and it really makes a difference.
For STEM types, if you want to get even more hardcore with your equations, I highly recommend learning LaTeX for equations. You can make your LaTeX work super easy by using it in Jupyter notebooks or similar software. Quarto is also a great option.