The steps to legally process a transfer of firearm to another individual in Illinois are outlined at the Illinois State Police website. The transferor (seller) simply inputs the purchaser's FOID number and date of birth into the ISP website. The page is located at: https://www.ispfsb.com/Public/Firearms/FOID/PersonToPersonFirearmTransfer.aspx
Simply enter the appropriate information and allow the search to reveal whether you can legally complete the transfer. If the inquiry states the transfer is permitted fill in the form and retain for 10 years. A copy of the form should be kept by both parties.