Why can't my friends not open my attached libre documents?

Have sent directions to two people who were unable to open the document.

I’ll hazard a guess that you probably saved your file in the default LibreOffice format (.odt for text files), which your friends’ operating systems might not recognize if they do not have LibreOffice or a recent Microsoft Office installed. Microsoft Office uses different default filetypes: .doc (older) and .docx (newer). Your options include:

  1. Suggest to your friends that they might like to download and try LibreOffice, as it won’t cost them anything;
  2. Save your file in a format that any system should be able to cope with, such as .pdf or .rtf. See the online documentation about how to do this;
  3. Assuming your friends have Microsoft Office, save your file in an MS Office-friendly format, eg .doc or .docx (again, see the online documentation - you can even set your LibreOffice preferences to always save in these formats if you wish); and
  4. When asking questions, please provide more detail about your system, what you did and how you did it. It makes it a lot easier to offer help.

Also refer the answer here.

Can you be more specific? What message do your friends receive? Which directions did you send? Are they using the same (or any) version of LibreOffice?