When completing a todo, simply click the “complete” button within the todo on Android, or in iOS, swipe left and choose “complete”. This will mark the task as complete for everyone who is invited to this task, so not everyone invited to perform a task will do the same thing.
As with an event, you must first accept the task that you will do it.
Once the task is completed – lottery ticket is bought, you click “complete” and the todo event will go to the archive and the owner will be informed his task is done.
If you by any chance lose the lottery ticket and need to buy a new one, simply press “reopen” and the task will appear again as not done.
From here, you can also “decline” the task, meaning it will be available for others to accept again.