Set Privacy for To-do

By default, all the users with access to the client can view the To-Do list, irrespective of whether the task was created by them, assigned to them, or someone else. However, should there be tasks you wish to restrict access to, either for yourself or specific assignees, you can mark them as Private.

The Task Privacy feature isn't enabled by default, so you must first enable it. Go to Settings > To-do Settings > Enable Task Privacy.

Once you've enabled the task privacy feature, you will see a Lock icon from where you can set the task privacy.