In your election's Basics step, you can set a start time, an end time, and a timezone — all optional.
Timezone
Choose the IANA timezone that should govern your election's times (for example, America/Chicago). This is the timezone your start and end times are interpreted in, and the one shown to you in status banners.
Start time
Leave Starts empty to open the election immediately when you click Launch election — invitations go out right away. Set a future start date/time instead, and the election launches in a scheduled state: invitations go out automatically at that moment, with no action needed from you. While scheduled, a banner confirms the exact start time and timezone, with a Cancel scheduled launch button if you need to back out.
End time
Set an Ends time to have the election close itself automatically at that moment — voting stops and results are computed without you needing to be there. Leave it empty and you'll close the election manually whenever you're ready, from the running election's page.
Changing your mind
Start and end times can be adjusted freely while the election is still a draft. Once it's launched, they're part of the locked setup — see Cancelling a scheduled launch if you need to undo a scheduled launch before it starts.