PAN (Permanent Account Number) is the Tax Identification Number in India, PAN is mandatory for opening Bank Account. PAN is mandatory for applying for GST, Import Export Code (IEC) and Various other registration mentioned above.
In the case of Pvt Ltd company registration, PAN is allotted along with the company incorporation itself. In other cases, PAN needs to be applied for separately.
Business entities are required to withhold tax from various payments like Salaries, Rent, professional fees, etc.
TAN is a number required to remit the tax withheld from vendors and employees. The company can have multiple TAN for different locations.