Singapore Visa Requirement:

Basic Document:-

Seven (07) months valid passport with an old passport if you have one.
Visiting card.
NID / Birth certificate copy.
Recent 2 copy photographs taken in the last 3 months (matt paper, white background only). 35 mm in width x 45mm in height
For First time visit to Singapore - Bank Statement and Solvency certificate are required (with a minimum BDT 80,000 ending balance)
V39A Invitation
Confirmed Hotel booking copy.

Air ticket booking copy.

For Business Person:- 

Renewal trade license copy with notary public ( English Translated )
Memorandum for limited company / Form XII
The blank page of office pad.

For Job Holder:-

No objection certificate (NOC)
BMDC certificate for Doctor 
BAR Council certificate for Advocate
Retirement document for Retired Person

For Student:-

Student ID card Photo Copy.
NOC from College/University
Birth certificate (Only for Child & infant).

Others:-

Marriage certificate copy (if spouse's name is not mentioned in the Passport)

Visa Fee Per Person: BDT 4,500 (Without LOI support) and BDT 5,000 with LOI support. (Non-refundable)
Note: Visa rate can change without prior notice.
Note:  Delivery time (7 to 10) working days
Note:  Visa validity is 60 days
Note: Visa issuance rights are reserved by the Embassy.