Why am I not able to install updates on my phone

You don't write which iPhone you have, but here you can see your options:

• Your iPhone 5S/6 can be updated to: iOS 12.5.7
• Your iPhone 6S/7/SE 1.Gen can be updated to iOS 15.7.3
• Your iPhone 8 or newer can be updated to: iOS 16.3.1

Remember to connect to Wi-Fi and a charger. Your iPhone must have more than 50% power to update without a charger connected.

You can find more useful information here:

If your iPhone or iPad won't update - Apple Support

If you want to update your iPhone via a PC or Mac, see here:

• Mac: Update your iPhone, iPad, or iPod touch with the Finder - Apple Support
• PC (iTunes): Update your iPhone, iPad, or iPod touch with iTunes - Apple Support

Hello ~ What happens when you try? Message? What is your current device and iOS? In the meantime take a look here by clicking on below…

If your iPhone or iPad won't update - Apple Support

~Katana-San~

1. On what iPhone model?
2. Which iOS version is currently running on it?
3. What happens when you try?