You can draw staccato dots, and staccatissimos using ink. However, sometimes it can be useful to quickly insert these articulations for many notes at once. This is where the Staccato and Staccatissimo brush comes in. To use, simply paint through the notes you wish to add the articulation to with the Pencil or pen.
Whilst you're inserting the symbol, you can the Pencil/pen up or down to change from staccato to staccatissimo.
To remove the articulations, paint through the notes again and and drag the Pencil/pen down.