Cacher is the code snippet organizer for pro developers

void OnTriggerEnter2D(Collider2D other)
{
  print("Entered Trigger");
  if(other.gameObject.tag == "[SOME TAG (Assign in inspector)]"){
    print("Entered trigger with tag!");
  }
}

/* To make the trigger, create a sprite and size it to whatever size the trigger
should be. Add a Box Collider 2D (or whatever collider you need) and select 
"Is Trigger". Disable the sprite renderer and add the tag you want, then
display it using the coloured tabs thing on the top left of the inspector.*/

// Assign a Rigidbody 2D to the object that is colliding with it as well.