Search and replace

I assume you are using Storyline. On the Home tab, there is a Find Text function which when expanded also allows you to replace text (incl. text in the Notes pages).

Another option that I like to use for this is the Translation feature under the File menu.

I use the export option to export all of the text in the Storyline file to a Word document (this includes notes, any text in states, markers etc). I then make my edits in the Word doc (including fonts changes if required) and then import the translation file back into Storyline.

I use Storyline 360 and there is no option under the Find / Replace feature to tell it to search the Notes.

hit crtl+f to open the find window