I want to update my phone

Assuming you have a compatible device, see: Update your iPhone, iPad, or iPod touch - Apple Support

And: If your iPhone, iPad, or iPod touch won't update - Apple Support

If the above Apple articles do not help, please post back with relevant information. 

Start here: Update your iPhone or iPad - Apple Support

FOLLOW THIS LINK: Update your iPhone or iPad - Apple Support

Update

Use the links provided in this thread.