Extension for October 15TH?

I was considering an filing for an extension for October 15TH. My goal is to continue contributing to my IRA so I don't owe as much for 2019.  If I file for the extension, am I still required to pay what I owe for 2019 on July 15TH or does this mean I don't have to start paying what I owe until October when I file? If I still am required to pay what I owe by July 15th, their wouldn't be any incentive to get the extension. 

 

Thank you.