Both Form 15G and Form 15H will make sure that TDS is not deducted on your income. Form 15H is a declaration under sub-section (1C) of section 197A of the Income Tax Act, 1961. And Form 15G is a declaration under sub-sections (1) and (1A) of section 197A of the Income Tax Act of 1961.
Some banks also provide an option to submit these forms online. But make sure you have a PAN card before applying for these forms. Remember, that both form 15G and 15H are only valid for one financial year. Therefore, if you are eligible you need to send these forms every year. Besides, submitting these forms as soon as the financial year begins confirms that the bank does not deduct any TDS on your interest income.
However, there are conditions you need to fulfill while submitting form 15G and form 15H.