what files will office libre work with? doc., docx. jpg?
LO can read and write many file types, amongst which several produced by M$ Office, graphics format and PDF. The files are translated into an internal format for processing.
Only the various .od? file types are guaranteed to keep the formatting you design. They are called “native format” files. They contain an exact representation for all features. In all other types, LO features and formatting must have an equivalent; if there aren’t, a “best” approximation is substituted. This is why sometimes, after a save-open cycle, you don’t see the document as it was. It depends on document complexity. Note this is more likely with .docx than .doc.