To notate any triplets, set the note duration to be the total length of the triplet figure, then press Ctrl+3. Quarter note triplets are three quarter notes in the period usually taken by two. So press 6 (the shortcut for a half note, the total length of the triplet figure), then press Ctrl+3.
Comments
Look at the picture here:
https://musescore.org/en/handbook/3/tuplets#Triplet_examples
To notate any triplets, set the note duration to be the total length of the triplet figure, then press Ctrl+3. Quarter note triplets are three quarter notes in the period usually taken by two. So press 6 (the shortcut for a half note, the total length of the triplet figure), then press Ctrl+3.