What does it mean to “seal the election”?

After you have created your election in the Online Voting System, it will be sealed by the system after you have confirmed that it should do so.

Once the election is sealed, all security parameters are activated and the data is distributed between the ballot box, electoral roll, validator, and election administration component. These subsystems are each protected and only communicate with each other in encrypted form. 

So when an election is “sealed”, it is secured and no further changes can be made.