Hey guys just wondering how high does the phantom 4 pro 2.0 drone go? I googled it an said 19,000 feet is that true?

Yes, that's true.
But not 19000 ft above your house.
You would have to climb to a high point in the Andes or the Himalayas and launch from there to get to 19000 ft which is the Service ceiling for the Phantom (highest altitude at which it can keep flying).
Otherwise, the drone has a limit of 1640 feet above wherever you launch it.

But be aware it may not be safe or legal for you to climb that high where you are.

In USA 400 feet is the law fly safe!

On a related note, I assume there's no way to know your altitude AGL where the drone is currently. I sent it up 400 feet, then flew towards a hill side. Before I got to the top of the hill and was barely above the treetops I realized if I set the altitude limit at 400 feet, it means 400 feet above where it took off, not 400 feet above the ground now.

Is there a way to know how far above the ground the drone is at any given time?

6,000m/19,685' ASL
500m AGL (as max flight altitude within the app given that the altitude reading is based on the height above the home point and not the surface below the drone)
120m AGL (default setting and typically the highest altitude legally permitted for recreational flying in most countries)

Autopump17 Posted at 7-25 12:28
On a related note, I assume there's no way to know your altitude AGL where the drone is currently. I sent it up 400 feet, then flew towards a hill side. Before I got to the top of the hill and was barely above the treetops I realized if I set the altitude limit at 400 feet, it means 400 feet above where it took off, not 400 feet above the ground now.

Is there a way to know how far above the ground the drone is at any given time?

- Pressure altitude is a measurement of the aircraft's altitude above a standard datum plane, and is indicated by setting the altimeter to 29.92. For pilots flying at an altitude above 18,000 feet, setting the altimeter to 29.92 is required to establish a standard for the aircraft.

120 meters legally in Ireland

Autopump17 Posted at 7-25 12:28
On a related note, I assume there's no way to know your altitude AGL where the drone is currently. I sent it up 400 feet, then flew towards a hill side. Before I got to the top of the hill and was barely above the treetops I realized if I set the altitude limit at 400 feet, it means 400 feet above where it took off, not 400 feet above the ground now.

Is there a way to know how far above the ground the drone is at any given time?

The drone does not know the altitude above ground until it enters Opti mode , then it is at 30ft.