Sending data to Blynk

I have a question about blynk
the only time the data be transmitted from Microprocessor to Blynk , it’s when I open the Blynk app from my mobile phone?
or it be transmitted even if I don’t open/use the Blynk app?
I’m completely confused about that issue…
Would you mind clarify it to me?

Provided that you aren’t using Bluetooth, your device will send data to the Blynk server regardless of whether you app is open or not.