how do i know if i have the latest itunes on my computer

source: https://support.apple.com/en-us/HT201352

If you downloaded iTunes from Apple's website

1. Open iTunes.
2. From the menu bar at the top of the iTunes window, choose Help > Check for Updates.
3. Follow the prompts to install the latest version.

If Check for Updates isn't an option in the Help menu, you downloaded iTunes from the Microsoft Store.

iTunes will let you know when an update is due when you open iTunes on your computer, it will then give you steps to update which are generally quick and easy.

Siabh wrote:

If Check for Updates isn't an option in the Help menu, you downloaded iTunes from the Microsoft Store.

In which case, updates are automatic and the user needs to do nothing.