Application for cancellation has to be made in FORM GST REG 16.The following details must be included in FORM GST REG 16-Details of inputs, semi-finished, finished goods held in stock on the date on which cancellation of registration is appliedLiability thereonDetails of the paymentThe proper officer has to issue an order for cancellation in FORM GST REG-19 within 30 days from date of application. The cancellation will be effective from a date determined by the officer and he will notify the taxable person