Is it possible to do a "Find and Replace" like you can do in Word?
No. And hopefully it never will be. OneNote isn't a Word Processor.
F&R is by no means exclusive to word processing.
It's a very valuable and powerful tool wherever text or code is concerned
and I'd like to see it added to OneNote as soon as possible too.
It would be interesting to see the scenario you are intending to use
this function with.
We use OneNote exclusively for our teachers to take lesson notes while
teaching students.
We recently changed the term "Trial Lesson" to "Introductory Lesson" and now
we want to globally change every reference to "Trial Lesson" in every page
of every section of every Notebook to "Introductory Lesson".
Students occasionally get married and change their surname. We'd like to
globally change their surname in every notebook to reflect their new name.
Etc.