To obtain Oman citizenship, passport and nationality by naturalization, one must meet the eligibility criteria set by the government. This includes residing in Oman for at least 20 years, being of good conduct, having a stable income, and passing a language proficiency test. The application process involves submitting the required documents, such as a birth certificate and a police clearance certificate, and paying the relevant fees. The application will be reviewed by the Ministry of Interior, and if approved, the applicant will be granted citizenship and issued a passport.