how do I share a libreoffice file with friends

When I send a LibreOffice file to friends, they cannot open it with MS Office. What do I do?

Please provide what version of MS Office your friends use. Some older versions of MS Office don’t support the ODF

The obvious answer is to get them to install LibreOffice or to use the portable app. That way they will get exactly what you send, unlike MS Office where there are differences between versions and OS.

If they cannot afford LibreOffice then you could Save as a copy in MS Office format, .docx, .xlsx, etc. for them, or export your file as pdf (File > Export as > Export as PDF) for them to read.

Don’t be tempted to save your own files in MS Office formats, that will lead to problems and regrets as you lose functionality that MS Office format doesn’t support.

In principle, M$ Office can open LO files (at least those produced by Writer, Calc and Impress). So, the simple answer is: send the original files. However, formatting primitives have been intentionally implemented differently by M$. You must then expect differences on non-elementary files.