Please help me vision

Hello ~ Your iPhone 5s cannot be updated to iOS 14. You will need a newer iPhone to download Apps that may need a higher iOS.

~Katana-San~

Your iPhone 5S can be updated to iOS 12.5.6.

What is the existing version of iOS?

While you seem to have already solved your issue, you should know that the iPhone 5S is not compatible with iOS 13 or higher.

That model can be updated to iOS 12.5.6, no further.