I want to marry my boyfriend Bangladesh and I am...

The Judicial Department of Oman is the official body responsible for issuing marriage certificates. Muslims can perform marriage ceremonies within the Judicial Department. Non-Muslims can also complete marriage procedures in the church or embassy concerned for both parties.
The required documents are:
Birth Certificates (Original).
Passport and valid residence copy.
A certificate of proof of the marital status of the parties (single, married, divorced) certified (if outside the country) by the Ministry of Foreign Affairs of the applicant and Consulate of Oman in that country (if in the country) by the applicant consulate and Foreign Ministry.
Certificate of healthy fitness for marriage