Q: My IPhone 6plus turned off since it crashed but now when I plug in it, the logo appears and then shut downs again. What do I do?

Today, my iPhone 6plus has been experiencing weird difficulties. It kept turning on and off since it kept crashing so much. I deleted apps and pictures to make more space to avoid this from happening. However, now the iPhone just turned off by itself and every time I try resetting the phone, the logo appears for a couple of seconds and then the screen turns black. So how do I solve this?