Citizens of a country enjoy the right to reside, work and receive an education in that country. In most cases, they have the right to vote and are entitled to social welfare, including pensions and public healthcare. However, citizens' rights depend on how much their country can afford to offer.
And, as the saying goes, nothing is for free. Citizens have to fulfil their responsibilities as members of the community. They must pay taxes to fund the development of infrastructure and support social welfare. They have to abide by the laws of their country.
In some countries, they must serve a term of compulsory military service.
In most cases, a person's citizenship is their nationality. If someone is an American citizen, their nationality is American.
But since Hong Kong is a special region not a country, Hong Kong does not offer immigrants a new nationality. Instead, they are granted permanent residency after living in the city for seven years.
A Hong Kong permanent resident can be from another country. They will be granted a Hong Kong identity card, and have the right to live in the city as a permanent resident.