Hi I m using iPhone 5s. I m trying to update my phone but it’s not showing any download option. Please advise me

• If you have an iPhone 5S or 6/6plus, the highest you can update to is 12.5.5

• If you have an iPhone 6S or newer, you can update to 14.8.1 or 15.1

Go to Settings > General > Software Update.

Update your iPhone, iPad, or iPod touch -

https://support.apple.com/en-us/HT204204

What iOS version is your iPhone running? Settings->General->About->Version

An iPhone 5s cannot update beyond iOS 12.5.5. If its already running that, there will be no further upgrade option available.

If its running anything lower than iOS 12.5.5 and you don't get an option to iOS 12.5.5 then you may need to use iTunes or Finder on a computer to update.

See here: link-> Update your iPhone, iPad, or iPod touch - Apple Support

If you can't see the update on your device, you can update manually using your computer. Learn how to update your device manually if you're using a Mac with macOS Catalina or later, or if you're using a Mac with macOS Mojave or earlier or a Windows PC.