Combining lenght of notes in a measure.

Hi everyone

So i've been looking for a few days now and i can't find on my musescore where can i combine different lenght of notes ? (like in the screen shot). I don't know the technical term for it and couldn't find anything on the help menu.

I got musescore 2.
Thanks a lot.
If i'm not at the right place or if there's a topic already done on the subject, just tell me and i'll check the link :)