How to increase inbuilt storage

You must sell your iPhone and purchase a new one to do that.

If you purchased your iPhone directly from Apple or an Authorized Apple Retailer in a brand new, factory sealed box within the last fourteen days, you may exchange it.

This is not possible unless you sell or trade the 128 GB phone and buy the 256 GB phone.

Hi naveenkumar49,

You cannot increase the internal storage on an iPhone as you would have to purchase a new device with a higher capacity storage. Hope this helps!

-MP