Office 2007-365 vs/or Office Open XML

Hi, I’m new to LibreOffice and I wonder which file format should I chose to save LibreOffice documents (text, presentation, spreadsheets) so they can be opened on Microsoft Office.
Thank you and best regards!

FAQ: How to open files from MS-Office 2007 or 2010 (.DOCX, .XLSX,…)?

To be on the safe side, save to Word / Excel / PowerPoint 97-2003. If you are sure that the recipient of the document has Microsoft Office 2007 or newer, save to Word / Excel / PowerPoint 2007-365.

Hi, thank you for your answer. However, can you tell me the difference between Office 2007-365 and Office Open XML saving options, since both formats use the .docx/.xlsx/.pptx extensions?

@zeca :I have the same question. As your comment is quite old and I can’t find the answer on the web, I post a new question