Most software is only too happy to provide an About box so you see the software version etc.
From Visio 2010 onwards MIcrosoft have decided not only to make it difficult to find the Visio About box but to actually not provide a menu entry for it at all. You have to edit the ribbon or Quick-access system to be able to get to it!
So, here it is, easy to get at now. Simples.