I have an iphone 6s. I need exact instructions on how to connect to my computer (which is not an Apple) which version itunes would I use?

Can you help me? I have an iphone 6s. I have never upgraded the software updates for many years. I need to upgrade the software to the 14 using my computer which is not an Apple. I do not know which itune to download to fit my phone (too many to choose) so I can update my software.

Download the most recent version of iTunes then do this: https://support.apple.com/en-us/HT204204

Download the most recent version of iTunes then do this: https://support.apple.com/en-us/HT204204

If it is a Windows 10 PC, start here:--> Download and use iTunes for Windows - Apple Support

When downloaded, carefully read section "Manually manage and sync your iPhone, iPad, or iPod touch".

Regards

Giulio