I am not sure where all of this information is coming from (I have seen other threads stating the same thing), but I assure you that MS-Office 2011 for Mac works with High Sierra.
Some possible areas of confusion might be coming from the following:
!. Microsoft will stop supporting this app. in October - it does not mean that it will not work, it just will not receive any further updates or security patches.
2. Apple is shifting to 64-bit apps., but not right away. High Sierra will be the last macOS to support 32-bit apps., which include: MS-Office 2011 for Mac.
So, for the next year (at least) you should be good to go.
Edit:
I forgot to add, that you do not need to convert anything, Pages will just open your Word documents. I am not sure how far that goes, I just opened a simple file with text only.