Charging mobile from 12V DC

Please suggest suitable and cheapest possible solution for charging mobile from a 12V battery,

Hello Lux_Manish,
welcome to MPS Forum.
We have a bunch of different ICs suitable for delivering 5V or even USB-PD to a mobile device. e.g. MPQ4481 can supply 5V with 3A to a USB-C connector – https://www.monolithicpower.com/en/products/automotive/usb-charging-port/mpq4481-aec1.html
Regards,
Samuel