How can I become a foreigner?

The foreigner you mentioned has a wide range. You can go to Africa, Vietnam, New Zealand and Australia. See which national policy suits your personal conditions. Do you want to go to an economically developed country? Or go to a poor and backward country? Generally speaking, no matter which country you go to, if you want to become a citizen of that country, you must first have money. Any rich country can easily become a citizen of that country and acquire the nationality of that country, then you can become what you call a foreigner. Do you have money with you? If not, you are a refugee in any country and no country will accept you.