Rests

Not sure, if your talking about multi measure rests, see: https://musescore.org/en/handbook/3/measure-rests#multi-measure-rest,

or if you purpose is to join measures for entering a rest it last longer than the actual time signature , see: https://musescore.org/en/handbook/3/measure-operations#join-measures

If you are talking about, let's say, a 2/4 tempo, you just have to add the whole rest silence into the first bar and the program will automatically put two tied half notes (splitting the original whole note into two bars).

If you are in 4/4 tempo, you can use the double whole note silence into a bar, and the program will automatically put two tied whole notes (splitting the original double whole note into two bars).