It can help improve FPS by a little bit but not as much as you'd hope. Todays GPUs auto overclock themselves to their thermal/power thresholds anyway. You can alleviate this a little by raising the power limits and improving the cooling so the card will clock a bit higher sure, but it's not going to be a night and day difference in what games/settings you can play at on a given card. There isn't much left under the hood these days in big performance gains especially so on the stock coolers. There is no amount of overclocking that is going to make a RTX 3060 play the latest triple A games at 4K/60 for instance. It's just not gonna happen. 
 
It can lower the lifespan of a card but as long as you don't do anything foolish like ignore your load temps or try to run a 1000w BIOS on a card with the stock cooler you'll be fine. They have lots of safeguards built into the card that will throttle itself long before you can do anything harmful to it. My advice if you're just getting into it would be to download MSI Afterburner and tinker around with some offsets for core and memory in increments of 25Mhz and just run some games and see if there is any uplift or decrease in the games you play. 

Jward89
Wow thank you so much,
I'm currently on a 1080p monitor, using a 3060 and average at 150 fps for warzone. My monitor is 165 hrz. If I tinkered with OC could I get the extra 10 to 15 fps?

You'd do better to overclock your CPU than your videocard but seeing as you're now banned I guess this advice is lost. 
 
 
PS: If you're reading this spamming the forums endlessly for your 100 posts to gain "elite" membership will get you banned. 20 posts in a day on a new account.......? Yeah bye bye