The deadline tells you when the Pay By Group will stop taking new invitees. If you're the group's organizer, you set it here.
You can still collect the group for up to a week after the deadline passes, but we recommend that you don't wait that long -- your invitees are expecting to be charged on or before the deadline.
If you need to edit the deadline for your group, just click on "make changes" and then move the deadline around. You can still do this even if your group is expired.
You can find the deadline for your group here: