Students desiring for post of officers in customs and excise department need to appear for UPSC (Union Public Service Commission) examination. Details regarding the examination can be found on UPSC website.
There are three ways, you can become customs officer.
1. Appear at Civil services Examination conducted by Union Public Service Commission. Besides IAS/ IPS/ IFS it recruits candidates for Indian Central Excise and Custom Services. If you join in right age, you can retire as chairman of CE and Customs board.
2. Appear at Tax Asst. of IT/ CE examination conducted by Staff Selection Commission. You can reach up to a rank of Dy Commissioner.
3. Appear at the clerical examination by Staff Selection commission and become officer by promotion.
For more details on UPSC Website Click Here