Do i need wifi router? or USB wifi Adapter will do the Job

my pocket is full of hole becoz of purchasing of Asus zenfone 6 (for me) & zenfone 5 (for sis). i want to share my pc internet connection with smartphone so do i need wifi router or any usb wifi adapter will do the job if so suggest me some good usb wifi adapter & wifi router without Modem (i will buy any one of them). is there any pro of wifi router over wifi adapter?thanks in advance.
budget ~2000 Rs