It is always good practice to have a comment header that describes what the application code does. This is also a good place to list out the Blynk data streams that you created for later reference.
For Example you can create a comment block as shown below.
/*----------------------------------------------------------------
Title: Blynk Relay Tutorial
Written By: (Place Your Name Here)
Date Written: (Place Date here)
Description: This code was written to control 4 individual relays
on an Particle Argon Relay Shield using four switch widgets on a
Blynk web interface and moblile app.
Blynk Data Streams:
Relay 1 (V0)
Relay 2 (V1)
Relay 3 (V2)
Relay 4 (V3)
----------------------------------------------------------------------*/