Open Document Standard (.odt) for all documents. In all public institutions (it’s already a NATO standard for documents).
Because the Microsoft Word ones (.doc, .docx) are unusable outside the Microsoft Office ecosystem. I feel outraged every time I need to edit .docx file because it breaks the layout easily. And some older .doc files cannot even work with Microsoft Word.
Actually, IMHO, there should be some better alternative to .odt as well. Something more out of a declarative/scripted fashion like LaTeX but still WYSIWYG. LaTeX (and XeTeX, for my use cases) is too messy for me to work with, especially when a package is Byzantine. And it can be non-reproducible if I share/reuse the same document somewhere else.