How do I download iOS 5.0

I'm assuming the iOS 5 was a typo.

• If you have an iPhone 5S or 6/6plus, the highest you can update to is 12.5.7

• If you have an iPhone 6S through 7, you can update to 15.7.5

• If you have an iPhone 8 or higher, you can update to 16.4.1

Go to Settings > General > Software Update.

This link will show you how to update your iPhone, iPad, or iPod touch using WiFi -

Update your iPhone or iPad - Apple Support Update your iPhone or iPad - Apple Support

This link will show you how to update using your computer -

Update iOS on iPhone - Apple Support Update iOS on iPhone - Apple Support

Twitter requires iOS 15.0 or later.

IF iOS 12.5.7 is the latest iOS security update for your iPhone, then you can’t update to a higher iOS (13 and later). 

The most apps require iOS 13.4 or later.                                

Considering a newer type of iPhone?

Read this before you buy a newer type iPhone.