my phone won't power off . when I slide nothing happens

Hello ~ Take a look here:

If your iPhone won't turn on or is frozen - Apple Support

~Katana-San~

Try Settings > General > Shut Down

My phone won’t power off and cancel won’t work I guess frozen

My iphone11 is frozen and will not "power off" and will not "cancel"

My iPhone 11 is frozen and will not power off