Yeah, according to this site:
Word 2008 is "questionable", at best, as to whether or not it works with Mojave. I actually was using Office 2016 for a number of years until an issue occurred with Outlook 2016, the EMail client contained in that suite. I then "moved" to Thunderbird, and it works fine. I, though, still used Word 2016 and Excel 2016. (By the way, it would be wise to look at that site to see if any of your other third-party applications work with Mojave).
However, I have been reading good things about the free suite LIbreOffice, and the "associated" package Open Office, for quite a while, and about 3 weeks ago, I "took the plunge" and installed LIbreOffice. Well, the "Word" and "Excel" modules it has work flawlessly in terms of reading and saving Word and Excel documents, no matter which Word or Excel formats they are in. I subsequently removed everything associated with Office 2016, including (of course) Word 2016 and Excel 2016. I did this on both of my Macs, and am quite pleased.
Also, I have been testing Mojave on an external SSD, and LIbreOffice works fine under OS 10.14.1. I suspect the same will be true for OpenOffice.
So, given that you want to use only something like Word 2008, you might want to download OpenOffice, available from here:
From there, you can decide which of its modules you can install.
As for Apple's Mail program, can't help you there, as Thunderbird works fine with Mojave. There have been a "fair amount" of other people who have had issues with Apple's Mail program and Mojave. Maybe make a separate post about your issues with it.