@agedrian1556 ...
It sounds like your instructor is not understanding how to specify acceptable files types for your assignment. Your instructor should not be specifying the software application (Word, PowerPoint, Excel, etc.). Rather, your instructor should be adding the acceptable file types that those software applications use. For example, if your instructor wants you to submit a Microsoft Word document, your instructor would add docx and maybe even the older doc file extensions (two of the common Microsoft Word file types) in the configuration options for the assignment. When your instructor enters "word", the he's telling Canvas that for this assignment, it will only accept a file with the *.word file extension...which is not what I'm assuming is the real intent. I'd recommend reaching out to your instructor as soon as possible to let him/her know that settings for this assignment need to be revisited so that you and your classmates can successfully submit the document for grading. You can contact your instructor by following the informaiton in this Guide:
How do I get help with Canvas as a student?
This is the Guide that your instructor would want to take a look at:
How do I create an online assignment? - Instructure Community (canvaslms.com)
Specifically, the section in this Guide called "Restrict File Types" near the bottom would be the most helpful...as it shows examples of how this should look.
I hope this helps a bit. Sing out if you have any questions...thanks!