Can I install Visual Studio Code on an iPad ?

Unfortunately no, because iOS - the operating system on iPads and iPhones - is not the same as macOS (formerly known as Mac OS X), the operating system for MacBooks, iMacs and Mac Pro computers. 

While they share substantial amounts of code under the hood, iOS is tailored for Apple’s phones and tablets. It does not have a traditional file system like a desktop computer, so you cannot download .zip files, .pkg, .dmg files etc. All software on iOS devices is distributed by the App Store exclusively. iOS has no support for mice or other traditional pointing devices, etc. so all software must be designed for touch interaction only. (Some apps support keyboard shortcuts with external keyboards, but not all.)

Microsoft Surface computers are different - they may have a tablet form factor, but they have Intel processors and run a full version of Windows; in essence they are thin, light laptops without a built-in keyboard. You can install most Windows apps on them (like Visual Studio), use a keyboard and mouse, or use touch and the Surface Pen, Dial, etc.