Till and until are the same and interchangeable. We use them to refer to the time we have up to an event or point in the time mentioned.
For example:
I’ll wait until 2:00pm, and then I’ll leave.
|————————————————| 2.00pm Now
We have until tomorrow to complete the budget.
|———————————————| Tomorrow Today
Give different examples of deadlines from your own life, using till/until.