I want to update my phone to iOS 14.0

You will need to tell us what model phone you wish to update. Older phones may not be eligible for newer updates.

I'm guessing that you have an iPhone 6 or iPhone 6 Plus. Can you confirm on that?

Not sure? Check Settings > General > About > Model Name

iPhone 6 can only go as far as iOS 12.5.7. Nothing higher than that.

If you want to run higher iOS versions, you need a new phone.

See message just above. Sorry, but you need a new phone.

I'm sorry, but you will need a new phone to run new applications.

Apple will not do this. Good luck.

I wan to update it to iPhone ios15.0

Go to settings - general - software update and start there.