my iphone keeps glitching, when i try to type something or open an app it types something different or closes out and the screen goes crazy what do i do?!

I have an iphone 8plus and it has been working perfectly fine until a couple hours ago. I realized the screen started glitching. For instance if I was trying to respond to a text the screen would stop working or would type letters im not touching or exit out of the app and it does this with all my apps. I have turned on and off my phone and I dont know what else to do!