You can create an AutoCorrect entry, where you type an abbreviation, and it
automatically expands into the organization name. Or, you can create an
AutoText/building block, where you either selected from a list (quick parts
gallery) or type an abbreviation and press F3 to expand it.
For AutoCorrect, type and select the full name and then click the Office
button - Word Options - Proofing - AutoCorrect Options. Put the shortcut
name into the Replace: field, decide on Plain Text or Formatted text, and
click Add, OK. Now, you can insert the organization name by typing the
shortcut and pressing space (or any word separator, such as period, comma,
etc.).
For a Quick Parts, select the organization name, and in the Insert tab,
click Quick Parts - Save Selection to Quick Parts Gallery. In Name: type a
shortcut you'd like to use. If you want it to be list-selectable, then leave
Gallery: set to Quick Parts. Choose or create a category (if desired, but
not necessary), and click OK. You can now enter the full organization name
by clicking Quick Parts and then clicking on it in the list (assuming it's
in the Quick Parts gallery), or by typing the shortcut name and pressing F3.