I want to update ios 12.5.7

To update to 12.5.7 -

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

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

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

If you already have iOS 12.5.7........there are no more updates for your iPhone.

I want you to update iOS 12.5

The answer has been given.

No one here can do it for you. Please follow the good advice offered by Kurtosis12 to do it yourself.

Updating ios12.5.7

Read through the previous posts.

I want to update iPad iOS 12 57