I want to know how to know about a person's settlement abroad, such as which countries he has obtained the right of abode, which countries he immigrated to and so on.

Like you, I would like to have a simple method, but the fact is that the world is so big that countries are not unified. If there is no standard method, it is a professional investigation, which is equally professional and lucky. Even our country can't know 100% whether a particular person has a green card in another country.

The general method is to collect information and narrow down the scope, and the chances of success are much greater:

Open solicitation: accurate name, date of birth, place of birth, school experience, work experience, overseas experience and relatives. ...

Comparison of government records: passport, driver's license, ID card, green card, birth record and household registration record. ..

Personal records: such as credit records, background records, travel records, accommodation registration, bank records. ...