Annotations are only available with the Premium or Ultimate Plans. They are not available if your board subscribes to the Essentials Plan.
It is the stage of a meeting that determines when annotations are available.
Available stages:
Published Agenda
Draft Minutes
Minutes in Review
To see what stage a meeting is in, open it from your Meetings page.
The meeting stage is shown on the top right of your meeting page.
You can then open your pack to annotate it by selecting the Board Pack menu and clicking on View & Take Notes.
Related Articles:
Meeting Stages and Flow
Adding Annotations