Printing the score

There is no "fit N measures on a line" command in Musescore. There are too many variables that determine the size of a measure to make that workable. In particular the size of a measure depends on the number of notes it contains, and hence the number of measures that can fit on a single line is similarly determined by the number of notes in the measure. You can fit several measures with single whole notes, but only a few measures that are full of 32nds).

But the good news is there are many ways of controlling the number of measures per line. I suggest you start by looking in the handbook, particularly here: https://musescore.org/en/handbook/layout-and-formatting, and then here: https://musescore.org/en/handbook/page-settings and here: https://musescore.org/en/handbook/layout-and-formatting#system-breaks and here: https://musescore.org/en/handbook/layout-and-formatting#layout-stretch

Preparing scores for printing is always going to involve a number of compromises and decisions. e.g. can I arrange it so that the page turn in a part follows a long series of rest bars? Can I get a repeat to start and end at the start and end of lines? Can I spread those measures out so that the final page is filled? Musescore leaves those compromises and decisions to the users (thankfully!).