Rest appearing itself

Hello ! I'm struggling for long with Musescore trying to write my harmony homeworks. When I start, I choose solo piano and start to write in 4 different voices. Randomly, the rest appear in every voice. Some I can delete some I can't. I read about input mode but I didn't find it anywhere to turn it off . Is there any tool which allows me to turn of the rest completely and add them only when I want to?

Thank you !