What is the ruling on immigrants changing their names or lineages upon obtaining citizenship in the countries they have settled in?

It is permissible to change a personal name if it is good or permissible, especially if there is a need to change it. The Prophet, peace and blessings be upon him, changed the names of some companions.

People have multiple ways of attributing themselves, such as birth lineage (to the tribe), place (to the location), profession (to the craft), madhhab (to the school of thought), and descriptive (to a characteristic). The Arabs used to attribute themselves to their tribes, then other forms of attribution became widespread after their mingling with non-Arabs.

It is one of the major sins for a person to disown their birth lineage and attribute themselves to other than their father. There are sacred texts that threaten those who do so with (minor) disbelief, stating that their action is among the greatest lies and fabrications, that Paradise is forbidden to them, and that they deserve the curse of Allah, the angels, and all mankind.

There is no harm for a person to attribute themselves to one of their ancestors or branches of their tribe, as the Prophet, peace and blessings be upon him, said: "I am the son of Abdul-Muttalib."

As for the attribution based on place, profession, madhhab, and description, it is an acquired and non-binding attribution, and there is no harm in changing it to another attribution, provided it is truthful.

A Muslim must preserve their name and lineage that indicates their origin, especially in foreign lands, so that their identity is not lost. If there is a need for change, there is no harm in it. However, the religiously forbidden act is disowning one's birth lineage and attributing oneself to other than one's father, as this is among the major sins.