This is an attempt to reproduce the Illinois letterhead in Latex. This uses the new brand, the block-I.
This the space-saving format outline here.
The official letterhead appears to use the Gotham font. A close available alternative is the Montserrat font, which is used here and is included in TexLive.
Copy (or link) the illinois-letterhead.sty and .pdf logo files to your working directory. In addition you will need sig.png or some other signature if you plan to use one. Then start with template.tex and modify.
You can see details by using the layout option: \usepackage[layout]{illinois-letterhead}. Setting this shows the measurements similar to here.
imarkbranch: This is the old I-mark style.blocki-basicbranch: This is this is the non space-saving original version of this template in the block-I format.blocki-nonpackagebranch: This branch uses\input{}instead of\usepackage{}