How do you edit fonts or labels in MainStage?

You can definitely edit fonts or labels in MainStage!

One tip is if you are just re-sizing things, in Edit mode, you can change the font in the inspector. If you open the font option and leave that open, you can then just select the text box and change the font and move pretty quickly (you don’t have to close the font and open it each time, MainStage will change whatever text you select which that font section opens).