If you are looking for Bangladesh Government portal for NID Registration (National identify card registration), you can apply online. You need your valid birth certificate and registered mobile number and email address for security verification.
Voter ID (photo ID) registration documents:
You need your father and mother’s name, NID for registration. If you have any brother or Sister or wife/husband available, you need their valid NID number during registration. Once registration done, you need to wait for approval. National Election Commission will send you messages once your registration approved. They will give you instructions to get plastic Smart. For online registration, you need to visit this link
How to get plastic smart card in Bangladesh:
You need to visit your local election commission office to apply for your smart card, plastic national id card. Local election commission hour is Monday-Thursday 9:00 Am to 2.00 Pm. They will scan your eyes for digital Irish print. They will send you message once your smart card is ready to deliver.