Question Power Supply for RTX 3070

Can you find out what brand and model it is exactly? If its a junk (Gold rating means nothing and neither does brand, its about make and specific model for quality) 600 watt I wouldn't put a 3070 on it, If its a good one then 600 watt should be fine, although most people are recommending 650 to be on the safe side.
 
i just remembered it is 650 watts and also i have a prebuilt pc from ibuypower so i dont know the brand of the power supply

Open up the side of the case and you should be able to find a label on the side of the powersupply, you may need to remove a PSU shroud from the top/bottom depending on the case.

As I said, it matters less how many watts a PSU is and more about the quality of the PSU, and most prebuilt have fairly low quality PSUs in them.