Which permissions do I need for editing?

At least writing permission

At the end of an activity, you can mark activities as completed. To do this, simply click the check mark in the column marked with the check mark. You can check activities in the schedule at measure level, at package and project level under schedule as well as your own activities even in your personal schedule in the dashboard!

Watch your step! By checking off an activity, the actual end date of this activity changes to the day of the change to "done"!

Click here, to learn more about finished tolerance.