Different barline at the end of a song

You've created your score incorrectly. You aren't supposed to create four staves just to get four lines of music. Your score should have only one staff. You should only add staves when you you want multiple instruments all playing at the same time. So your score is actually only four measures long, with the four staves you see all playing at the same time. You'll see that if you press the Play button.

Instead, you should have only one staff, but have sixteen measures. MuseScore will automatically wrap the stafft o multiple lines, just like word wrap in a word processor. And if you want to force line breaks to occur somewhere other than where the automatic wrap occurs, you can force line breaks wherever you want - just click a barline and hit Enter/Return. Again, just like a word processor.

Btw, you also attached the backup version of your score. The real score wouldn't have had a comma at the end of the filename (or a period at the beginning).