I entered chords for guitar and they appeared on all of the other parts.
Layout Options > Chord symbols and diagrams > Above top staff of system,
or
go to Setup Mode, and right-click the players in the left panel to get to the menu item Chord Symbols.
This is because chord symbols by default are system objects, meaning they apply to all instruments and automatically show above rhythm section instruments (more info here). You can hide/show chord symbols for all instruments held by a player or just specific ones, and hide/show them in different layouts.