My iPhone is not turning on and I don’t want to loose some important documents on its WhatsApp

Hello, thank you for using Howly. I’ll be happy to help you out! May I ask your name?

Nice to meet you, *****!
What do you see on your iPhone screen when you put it on charge?

Got it, and when you try to turn it on, does it turns on, and do you see any message on the screen?

Tell me please the iPhone model

Thanks, let's put it into the Recovery Mode
Disconnect it from charger
And then - Press and hold the side and volume down buttons at the same time.
Keep holding them until you see the recovery mode screen.

You will see the iTunes logo on screen

Excellent
Please follow the next steps:
Open iTunes on your Mac. Connect your iPhone 7 Plus to the computer via a USB cable. If a pop-up occurs on your device screen asks for your device passcode or to "Trust This Computer", follow the onscreen steps.

Ok, I got it. Then you need to install it, first.
Here is the link https://www.apple.com/ua/itunes/download/

Which version did you try to download?

Please try this one https://updates.cdn-apple.com/2019/cert/041-88776-20191023-0597F90B-921F-459B-91CA-34108771225E/iTunes.dmg

Oh, ok
Click the Finder icon in the Dock to open a Finder window, click the iPhone button in the Finder sidebar (below Locations), click General at the top of the window, then click Restore iPhone.
So you still need to connect the phone to the Mac with a cable.

Ok, good

Please reconnect the phone, and if still no phone, restart the Mac.

No, you just need to open the chat again.
For your convenience, here's the link - https://howly.com/chat

Does your Mac recognize the iPhone now?

Is your iPhone currently in Recovery mode?

Try to connect your iPhone with cable to another port, on your Mac
And check if it appears in the Finder sidebar

Okay, disconnect your iPhone from the cable and leave the cable connected to Mac
Power off iPhone holding - Volume Down + Side button

I mean power Off from Recovery Mode

Is the Laptop logo on the screen right now?

Excellent, please, press and hold the side and volume down buttons
To enter Recovery Mode

Got it, look's like the battery has no charge
Please put it on the charge for a few minutes

Thanks, allow it a few minutes to charge after that we put it in Recovery Mode one more time

Connect it to your Mac one more time
Let me know how everything is going.