edit and save preexisting files

edit

Hi

It should perhaps clarify your question, but the answer is that you have choice: you can open, edit, save in their original format, or, what is recommended, you can save them in native format LibreOffice.

This is recommended because it avoids format conversions that are (mostly) potential sources of rendering differences.

Note: With File▸Wizards▸Document Converter you can convert "batch" of sets of document.

Regards