Hello,
Please read the explanation visible in your screenshot for the "registration" setting. And please follow these instructions.
As also visible in your screenshot, if you want to have guest checkout features, you need to use commercial editions of HikaShop (essential business).
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.