You can also make a new .cfm file and use it as a function library. You can then use the cfinclude tag to include it on any pages that might need it.
cfinclude only has one attribute, template, that takes the path to the function library file. If the function is placed in a file called greetingCustomizer.cfm, to give our page access to the function we just include our greeting customizer on the page like so:
<cfinclude template="path/to/libraries/greetingCustomizer.cfm" />