Hello @JoeKim,
Custom Toolbars are stored as XML-files in a separate folder for each Office module. For example on Ubuntu the custom Toolbars for Calc are located in:
"/home/user/.config/libreoffice/4/user/config/soffice.cfg/modules/scalc/toolbar/"
These XML-files can be edited with a plain text editor.
You could just send that XML-file to your recipients by E-mail, with instruction to place it inside the folder mentioned above, or the equivalent folder for their system.
Then restart LibreOffice, the custom Toolbar should be selectable from the View:Toolbars menu. Please let us know if that works.
-i think- it is required that the file name starts with “custom_toolbar_”, and the next part can be changed into something unique.
Regards, lib