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Form 12BB, every employee has to submit self-declaration to his employer at the starting month of the year say for the financial year 2017-18, they have to submit their declaration during the month of April 2017, in which an employee gives estimated figures to claim their investments, house rent paid, interest on home loan, leave travel allowances etc. to his employers. after submitting the declaration, the employer calculates his estimated taxable salary after allowing deduction and their savings, TDS will be deducted every month from his salary. At the end of the year, the employee should submit form 12BB along with their proofs, against the declaration previously made by him. The proof amount can be lower or higher from the declaration given by employee