Find and replace what?
You posted this in the devices subforum, which deals with... device connectivity. I confess I am not sure how you would use a find and replace to modify the device you have connected to your computer.
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Are you referring to metadata? ("Library Management" subforum)
Right-click Edit Metadata (is a toolbar icon) ==> Edit metadata in bulk ==> Search and Replace (third tab)
The content of the book? ("Editor" subforum)
The E-Book Editor has a dedicated "Search" section in the "File... Edit... View..." menubar.