LaTeX is a system for document-preparation and typesetting. In my corner of academia (physics, mathematics, computer science) it is also the method de rigueur for the preparation of manuscripts. Many academics in my field reach out for LaTeX by default when writing anything on the computer. I am no exception.
This is a basic template for filing NSF grant applications; the formatting and required sections should be current as of the 2018 Grant Proposal Guide.
A nice feature is that it uses the childdoc package to enable the easy compilation of the various "sections" of the grant proposal into standalone PDF files ready for upload to Fastlane/research.gov. The file MASTER.tex should only be edited to include more preamble stuff that you need; compiling it will produce one big PDF file including all parts of the proposal (convenient for sending to your chairperson to review).
Each of the individual numbered TeX files can be edited and compiled separately, cross references and citations are automatically handled.
Michigan State University has published letterhead for use by faculty and staff in Microsoft Word format. I reproduced the formatting in LaTeX, including the use of Arial (Helvetica in fact) for the information in the scholar's margin. The PDF version of the MSU wordmark and seal are converted from the Postscript ones available for download on the MSU brand website. The tarball only includes the PDF logos for size considerations (the Postscript files are huge).
If you ever find yourself needing to add postscripts after the signature (for example, using the letter as a cover letter with further attachments, or having additional appendix pages on your letter), please note that the class is based on the LaTeX letter class, which means that the \closing command disables subsequent page breaks. To work around that, you would need to manually issue \startbreaks as described in this TeX StackExchange answer.
textpos package. Margins defined using the geometry document. The positioning of the marginalia should now be stable across changes of paper sizes (but it would not look good with legal paper; you would need to fix that yourself if you use paper sizes much different from letter or A4).I have some other LaTeX resources on my MSU GitLab Repository. This includes some heavily customized LaTeX class files for preparation of my lecture notes, as well as for preparing documents for printing with the Espresso Book Machine. One of the things I am somewhat proud of is some code for producing annotated cross references. Also included are some miscellaneous packages that I wrote at one time or another.
If you are curious: I do most of my editing on Linux-based systems. In my office my desktop computer runs arch linux. I use the i3 tiling window manager, and most of the time my screen is covered with terminal windows. When out of my office my computer is a Google Pixelbook running ChromeOS. I make heavy use of Project Crostini and have a container running arch, and instead of the built-in ChromeOS terminal, I use Tilix.