These are the receiver catching controls introduced in Madden NFL 16.
After you throw a pass, you can tap or hold the corresponding button to tell the receiver to attempt a specific kind of catch. You do not need to use Circle (PS5) / B (XBOX) to switch onto the receiver first, just tap or hold the corresponding button as the ball is in the air.
Triangle / Y: Aggressive Catch - the receiver will attempt to high-point the ball and pluck it out of the air
Square / X: RAC Catch - the receiver will attempt to catch the ball without breaking his stride
Cross / A: Possession Catch - the receiver maximize ability to and focus on catching the pass, but sacrifice run-after-catch opportunities