LaTeX is an open-source suite of software tools for typesetting professional-quality documents, presentations and posters. It is particularly well-suited for writing mathematical documents, because it provides extensive support for typesetting mathematical equations and objects such as vectors, matrices, arrays, etc. It is also straightforward to use graphics and other media in your documents. In the end LaTeX typesets the document in the form of a PDF file.

Although it is possible to download and install LaTeX on your own devices, there are also various websites that provide online access to it without downloading anything. It is much easier to get started by using such websites.

LaTeX has been around for a few decades, and has proven its ability to survive and thrive even in the midst of the rapidly evolving technological landscape that has rendered most other word processing systems obsolete. Many people and places have thoughtfully assembled LaTeX learning resources online, and it would be foolish for me to duplicate their work or to try to outdo them. Here are some such resources to get you started

• Overleaf, an online LaTeX editing and typesetting resource

• Prof. Schumacher's LaTeX site at Kenyon College
  In particular, check out this introductory user guide posted there.

• Getting started guide by TUG (TeX Users Group)

• Another good beginners' guide from Cornell U.