Is it permissible, in Sharia, to write the family name by omitting the ya of attribution (ya al-nisba), such as writing "Al-Zahran" instead of "Al-Zahrani," even though it appears in official documents?

It is permissible to attribute a person to their tribe by adding the yaa' of nisbah (relative adjective), such as "al-Zahrani," or without the yaa' of nisbah, such as "Zahran." The linguistic norm is to append the yaa' of nisbah when attributing to tribes and countries. Linguistic evidence indicates the permissibility of both forms. There is no religious impediment to a person writing their name and family name with or without the yaa' of nisbah, especially if this is common practice and does not result in an external impediment.