On Seed&Spark, your campaign is successful (meaning you'll receive all raised funds after it ends) when you reach at least 80% of your goal.
We call this getting the Green Light.
You can get the Green Light at any point while your campaign is live. Once you've received the Green Light, you can keep raising funds until your campaign ends, even beyond 100% of your original goal.
When your campaign receives the Green Light it typically must still run for the full duration you originally selected before the pledge collection and payout process can begin.