all apps on old iphone will automatically transferred to new phone

If you are asking will all of your old iPhone's apps transfer to a new iPhone, the answer would be maybe. Apps that are not compatible with the newer version of iOS may not transfer. Otherwise, the new phone will have the basic Apple-provided apps already, and most third party apps that you got originally from the Apple App Store, will need to be re-downloaded. Typically that is done via the transfer process.

Ref: Transfer data from your previous iOS device to your new iPhone, iPad, or iPod Touch - Apple Support