TO CHANGE THE TERMS OF A PRINTED FORM IN WRITING, MUST THE WRITTEN CHANGE BE INITIALLED?

It depends on the form and what it says.  if it says it cannot be changed or has to be changed in a certain manner, you need to comply with those requirements.  to generally change a written document, you need a written document that needs to be signed by all parties that signed the original document.  initializing the individual pages will help as long as somewhere, usually at the end, the changing document is signed, dated, etc.  good luck.