The full name is the Document of Identity for Visa Purposes, Hong Kong Special Administrative Region, People's Republic of China (abbreviated as DI), which is a travel document issued by the Hong Kong Immigration Department to the following categories of people:

1.Persons who have been granted temporary residence in Hong Kong but are unable to obtain a passport from any country or other travel documents from other regions;
2.Persons who have been granted unconditional stay in Hong Kong but do not possess the right of abode in Hong Kong and are unable to obtain a passport from any country or other travel documents from other regions;
3.Non-Chinese individuals who have obtained the right of abode in Hong Kong and hold a Hong Kong permanent resident identity card but are unable to obtain a passport from any country or other travel documents.

In short: Issued to residents living temporarily or permanently in Hong Kong without a passport from their original nationality.

The Hong Kong Document of Identity is different from the Hong Kong SAR passport; the Document of Identity does not provide visa-free treatment. Holders of the Document of Identity must apply for a visa in advance when traveling abroad. The Document of Identity mainly serves as a document for applying for foreign visas and can be used as a valid travel document for immigration visa applications.