To apply for Bangladesh visa, the applicant must submit original passport valid for at least 06 months with minimum two blank pages. Visa application must be submitted to the High Commission in a prescribed visa application form along with 2 (two) recent passport size photographs with white background. You can download online visa application form here.
Incomplete application form or application with incorrect information or insufficient supporting papers may be rejected without citing any reason thereof. Applicant may be called for an interview if it is felt necessary by the visa issuing officer.

Student Visa

1. A letter from Government approved Educational Institution of Bangladesh where the applicant has gotten admission or is going to be admitted
2. Sponsorship letter from the concern Educational Institutions of Bangladesh
3. Last three month's bank statements of Applicant/Sponsor
4. Applicant must bring acopies of all educational certificates as well as Student ID Card
5. Two(2) Passports Photographs
Duration of Student Visa is Maximum one (01) year. Visa may be further extended from Bangladesh

for more information : http://www.bhcnigeria.org.ng/Visa.html#:~:text=To%20apply%20for%20Bangladesh%20visa,size%20photographs%20with%20white%20background.