Rests

I'm not entirely sure what you mean, but you can make a rest invisible by selecting it and pressing V, overwrite it with notes or cut and paste, and delete unused measures at the end of a piece with [Ctrl]+[Delete] (Mac: [Cmd]+[Delete]). Are any of those what you're looking for?

Additional information:

In voice 1, each measure has to have the correct number of beats. So there is no such thing as "getting rid of" a rest - that would leave too few beats in the measure. You can only replace it with a note (or multiple notes adding up to same duration) - that's the only thing that makes musical sense.

If the notes you want to replace the rest with are already present somewhere else, you can copy/cut and paste the passage from the old location directly on top of the rest. Or you can simply enter the new notes directly on top of the rest.

In other voices, one should normally show all beats as well, but there are some very specific situations where the rules of notation allow rests to not be shown, and in those cases, you can make the rests invisible or even delete them.

If this does not answer you question, please post the specific score you are having problems with (see "File attachments" link right below where you type your reply) and describe precisely what you want to do.