We are using "STM32G473VET6" MCU in our design. And we are connecting same voltage of 3.3V to VDD, VDDA and VREF+. Is that the correct way or we need to change power supply for VREF+ ?

[KnarfB]

There is a nice app note "AN5093 Application note Getting started with STM32G4 Series hardware development boards" with a ref design.

You can use the same voltage for VREF+, you can/should filter it (see ref design) for better results or you may use some external (more precise, independent,different) ref. voltage if you prefer.