For MuseScore 3 users, see Tremolo
Tremolo is the rapid repetition of one note or a rapid alternation between two or more notes. It is indicated by strokes through the stems of the notes. If the tremolo is between two or more notes, the bars are drawn between them.
The tremolo palette contains separate symbols for one note tremolos (shown with stems below) and for two note tremolos (shown with no stem below).
In a two note tremolo every note has the value of the whole tremolo duration. To enter a tremolo with the duration of a half note (minim) first enter two normal quarter notes (quavers). After dragging a tremolo symbol to the first note the note values automatically double to half notes.