Update iOS 13

These are the iOS options based on iPhone Model --> You need to Identify your iPhone model - Apple Support

• iOS 15.7 —> 6S / 6S Plus, SE (1st Gen), 7 / 7 Plus,
• iOS 15.7 or iOS 16.0.2 --> SE (2nd and 3rd Gen), 8 / 8 Plus, X, XR, XS /XS Max, 11,11 Pro /11 Pro Max, iPhone 12, 12 Mini, 12 Pro, 12 Pro max, iPhone 13, 13 Mini, 13 Pro, 13 Pro Max, 14, 14 Plus, 14 Pro and 14 Pro Max
• iOS 12.5.6 —> Final release supported on iPhone 5S, iPhone 6/6 Plus, 

Learn how to--> Update your iPhone, iPad, or iPod touch - Apple Support

It depends on your iPhone model.

See this compatibility list: