To fix/reset Microsoft Word 365 to normal settings

Microsoft word is not behaving properly. Save documents when I open them again have a different format and font, small text size letter and poor plain style, than the originally format they were saved. Also Trying to create a new document is a big issue. I have and iMac 2018, I installed and installed Microsoft word 365 version 16.66.1, which I purchased at the beginning of this year. I upgraded my operating system from Monterey to Ventura., but before doing this changes, Word was already acting up. It doesn't follow simple commands.. Would you tell me more about your services and fees for this issue Thx Betty