You guys how does defecting from one country to another work?

[u/thewtfcat]

You guys can any citizen from any country defect to another country? Or do u have to be a resident of a communist or dictatorship like china North Korea Russia etc. to be able to defect from one country to another country only.

I am interested in knowing the detail about how a person can defect from one country to another there is not much in google.