Depending on whether you have a Review or To do task, or a site invitation open, you can
tap a choice of action buttons.
Approve: Approve the reviewed file or accept the site invitation.
Reject: Reject the reviewed file or site invitation.
Reassign: Choose another person to assign the task to.
Done: Complete the task, and add a comment if required.
Tip: Once you've approved a site invitation, just refresh your sites list by pulling
down, and you'll see the site you've just joined in the list.