Why I save doc documents in LibreOffice, and they don’t properly save?

I have a Dell laptop. I don’t have Microsoft Office, but I have download LibreOffice. It is a nightmare to save documents that won’t be save as a Microsoft Office, so every time I open the doc I am aske to open Microsoft acc. and get the program or else the document needs to be recover… How can I save the document in my Documents like in the old good days…?
Many thanks