These programmes trade investment for a residence permit: common routes are a qualifying real-estate purchase, a capital transfer, a business investment or government bonds. Residence may lead to permanent residence or, after years, naturalisation — but that is a separate, slower path with its own tests.
The detail is everything and changes often: minimum amounts, whether property qualifies, physical-presence requirements, family inclusion, and tax consequences all vary by country and year. Several European property routes have recently been tightened or closed; Gulf programmes like the UAE golden visa remain active.
Buyers should never choose a property purely for a residence permit without confirming the current immigration rule and modelling the tax effect of becoming resident — residence can expose worldwide income and gains to a new tax system.