Where can I download iOS 12 download for my MacBook Pro Mid 2012 I have iOS 10?

Hi aminu-dan

welcome to the Apple (user-to-user) Community!

Seems you have MacOS Catalina 10.15 installed on your Mac, and would like to upgrade to a newer MacOS version: However, according to: Identify your MacBook Pro model - Apple Support

MacOS Catalina is the newest compatible operating system that can be installed on MacBook Pro Mid 2012.

What's new in the updates for macOS Catalina - Apple Support says: macOS Catalina 10.15.7 provides important security updates and bug fixes for your Mac.

To check if you already have MacOS Catalina 10.15.7 or still have an earlier version of Catalina:

choose Apple Menu (black apple at top left in menu bar) ... then click "About this Mac" to see your MacOS version.

Else: If you do want to update to Mac OS Catalina 10.15.7:

choose System Preferences from the Apple menu , then click Software Update to see if the update is waiting.

All the best :-)

macOS 10.15.7 (Catalina) is the latest version of macOS (not iOS) available for your Mid 2012 MacBook Pro.