You can add a text label to any beat using this button in the palette.
You can attach a dynamics marker to any beat, using the palette.
There is an option in the Score Settings to always hide these markers if you just want the sounding but don't want them to be displayed/printed.
Several accents and anti-accents are available in the palette.
A ghost note
Accents and strong accents.
Chord names and diagrams
Add a chord name or chord diagram to your compositions.
Chord names are attached to the measure and will be displayed at the top of the first staff.
Chord diagrams are attached to a specific staff and will be displayed only for this staff.