Question

can anyone write a farewell speech for a office staff of your school

Answer 1

Farewell speeches mark significant departures. They are so much more than a casual "see you later" and a mumbled "thanks for everything"  as you make a dash for the door.

A planned goodbye speech crystallizes the moment of leaving, giving it focus, form, and dignity.  It provides an opportunity to publicly acknowledge people and events, as well as to graciously show your appreciation and gratitude for them.

And that, I think, is the sort of speech you want to give!