When inputting music in multiple voices, rests are normally created automatically when there is a gap in the secondary voice. However, if you want secondary voices to begin with explicit bar rests in strict contrapuntal music, you can input a bar rest into those voices.
For music in a single voice, you do not have to input bar rests as they appear in each new bar automatically when you advance the caret. You can also hide/show bar rests in all empty bars in each layout independently.
Procedure
Result
Bar rests are input into the selected voice at the caret position. If the caret position is within a bar that contains notes for the selected voice, these notes are replaced by the bar rest.
Alternatively, you can click Insert Bar Rest in the Insert Bar Rest section of the Bars and Barlines panel to input bar rests during note input.