Google Drive Upload Conversion Issue

I've been attaching my vendor's (tutors) schedules, so that my colleagues and I can access their availability when we search for their name. The first time I uploaded one via Google drive, the file opened as a Google drive file & I was able to make updates that saved automatically. Since then, all the subsequent updates have changed the file format to open in either Zoho docs (where I can make changes, but can't save) or it opens as an MS office file (where I have to open another 3rd party software that cannot save the changes or communicate with Zoho).

Is it possible to permanently change my settings so that all of the Google drive files I upload will remain Google drive files that I can edit & save the changes via Zoho? Or will I keep having to upload a new file every time I make an update?