The person who received the activation code from you is called the activator. In the event of your death or loss of capacity, the activator enters the activation code at https://app.securesafe.com/app/activate/#/, triggering the probate process.

Will data be transferred immediately? What is the blocking period?

The files and passwords are not transferred immediately after entering the activation code. The blocking period (a security waiting period) must first elapse. During this period, you as the account holder can stop the inheritance process.