Method 1:
In annotation toolbar, after selecting a tool, tap on the preset to change annotation style properties:
In annotation toolbar, after selecting a tool, tap on the preset to change annotation style properties:


Method 2:
Select an annotation you want to change, select Style, then select the color, thickness, opacity you want to change:
Select an annotation you want to change, select Style, then select the color, thickness, opacity you want to change:

