The Annotation style section contains icons for configuring annotation colour and transparency.

All annotation styles are set by clicking the icon and choosing a colour, number, or percentage from the dropdown menu.

Clicking the annotation colour lets you choose the outline colour of your annotation

Clicking the annotation thickness lets you choose the thickness of the line of your annotation

Clicking the annotation opacity lets you choose how opaque/transparent your annotation outline is

Clicking the fill colour lets you choose the fill colour of your annotation (if its a closed shape)

Clicking the fill opacity lets you choose the fill opacity/transparency for your closed shape annotations e.g. square, closed freehand