how to fix .odt doc that opens as graphic

I had created an .odt document and saved it as such. The next time I needed to enter the document, I was asked which application to use. I chose Chrome since LibreOffice Writer wasn’t offered. The document opened as a graphic Open OfficeDraw even though the system still named as an .odt. What should I have done differently, and more importantly, how can I convert the doc back to an .odt? Thanks for your response.

Which OS are you working with?