Every time I’ve tried to send an email with a LibreOffice document attached, none of my friends/colleagues with Microsoft Office can open and access what I send - what’s the answer please - Thanks!
If you aren’t already doing so, try saving the LO documents as .doc (preferable) or .docx.
Lady Fitzgerald, thanks for this tip ma’am!
Lady F - saving as .doc did the trick - THANKS!
In addition to what @LadyFitzgerald wrote:
I would suggest you create a .doc (or .xls or …) version only for the exchange, and keep your file in OpenDocumentFormat for your work.
Avoid multiple editing of files using MS-Office and LibreOffice alternating. This is known to cause problems.
Trying an explanation. No guarantee as I lack experience in some respects!
There cannot be full compatibility anyhow, but MS implemented a (incomplete) capabilty to open LibreOffice files in recent versions (starting with Office 2007 Sp2). If your colleagues cannot open any file of the odf family at all, I would suppose they are working with older versions of MS Office (V 2003 2007 without an update). In this case they probably also cannot open recent .docx (or .xlsx …) files. (And even MS Office 2013 is by default using the “transitional” open format of MS’ own brand. Some suppose it’s a mess. The only truely open standard is odf.)
Thanks for this info Lupp!
Your friends could pay for a less older MsOffice version maybe - already MsOffice 2007 SP1 started to support ODF.
Alternatively: installing LibreOffice is cheaper 
Office 2007 reached EOL (End of Life) on the 10th of this month so it is no longer supported by MS and should be replaced. The oldest (and, in my not so humble opinion, the best) version of Office still being supported is Office 2010, which will be in extended support (security updates only) until 10/13/2020.
(Stupid word count limit!) Something else that may help with MS Office compatibility issues would be to create a Libre Office template from an MS Office blank page document. It has helped me with other compatibility issues.
If your documents are to be read only, you may consider saving and sending them as PDFs. PDF is the best cross platform file one can use. LibreOffice has the ability to save files as PDFs and can even be set to have the original LibreOffice file embedded in the PDF to enable you to easily edit the PDF later on within LibreOffice.