You're confusing two things:
HK Re-entry Permit is a HK-issued document enabling you to re-enter HK after travelling to the mainland. It is only useful for a very small group of people. From
https://www.immd.gov.hk/eng/service/...ry_Permit.html :
People Who Do Not Need an HKSAR Re-entry PermitUnder the Easy Travel Scheme, holders of Hong Kong identity cards bearing "***", "*" or "R" symbol or locally issued Hong Kong permanent identity cards, who are aged 11 or above, can travel from Hong Kong to the Mainland and Macao SAR and vice versa without producing a HKSAR Re-entry Permit or other travel documents at any Hong Kong immigration control point. They are also not required to fill in any arrival card or departure card.
What is commonly (though not entirely accurately) called a "Home Return Permit" (more accurately a "Mainland Travel Permit") is a document issued by Mainland China (not HK) enabling you to enter the Mainland. HK and the Mainland are two separate "countries" as far as Immigration is concerned. You need to deal, in Chinese, with CTS, which is the sole agent of the Mainland authorities for issuing these documents, as noted previously.