Fundamentally, part A of form 16 provides summary of tax deducted from your income and deposited to the government as per the monthly and quarterly TDS return filed by the employer.
Part B is an annexure containing details of salary paid, other income, tax due and tax paid. This is a complete detailed record of salary and related deductions and exemptions computed in a step by step manner.
This part of the Form 16 is a complete detailed record of the salary of an individual. The name and PAN of the employee are quoted even in this part of Form 16. It contains details of
1. Gross salary,
2. Exemptions claimed under section 10 of the IT Act and
3. Net taxable salary after deducting these exemptions
4. Details of house property income
5. Deductions from salary under section 80 C to 80 U
6. Amount of tax on income
7. Income tax paid and hence either taxes due or refund due.........
More details refer: difference-in-salary-amounts-between-part-a-and-part-b-of-form-16