how do i get rid of a black rectangle covering my iPhone screen? can't go to settings, everything is frozen. can't restart according to directions

Next see the process below

 If your iPhone is stuck on the Apple logo - Apple Support

There is no guarantee you can save any data since your last backup if you need to use the Restore option.

After that you should arrange a repair

https://support.apple.com/iphone/repair/service

or: contact Apple Support 

Anything other than Screen or Battery may be a replacement phone and the price is in the article.

You can see additional service information within the following article:

Prepare your iPhone for packing and shipping

Try a forced restart.

• Press and quickly release the volume up button

• Press and quickly release the volume down button

• Press and hold the side button.

• When the Apple logo appears, release the button.

https://support.apple.com/en-in/guide/iphone/iph8903c3ee6/ios

If the process that I advocated, and recommended by Apple, does not work more than twice, your phone is probably toast.

Arrange a repair or more probably a replacement

 iPhone Repair - Official Apple Support

or Contact - Official Apple Support

Anything other than Screen or Battery may be a replacement phone and the price is in the article under "Other damage"

Hello ~ Try this version previously posted by *Axel Foley*

(1) Try and Force Restart your iPhone EXACTLY as shown below and see whether that resolves the issue:

• Press and quickly release Volume UP button
• Press and quickly release Volume DOWN button
• Press and Hold the SIDE button until an Apple logo appears and then release the Side button (Can take up to 20 seconds. (DO NOT release Side Button when invited to Slide Power OFF). 

~Katana-San~

I still cannot activate my phone it reverts immediately back to a black screen