Error 6753 while copying new iphone from old one.

Hello hammad162 and welcome to Apple Support Communities. It appears you are having some difficulty setting up a new iPhone and that it is failing with the error code -6753.

This error code most often comes up when the transfer or setup process has been interrupted and starting everything fresh is most often the reported solution.

Use Quick Start to transfer data from your previous iOS device to your new iPhone, iPad, or iPod touch

If the tips there do not resolve the issue, you'll find a link at the end of the article that will direct you to contact Apple Support for further help.

Cheers.