Advance tax is also known as pay tax as you earn. It should be paid in advance during the financial year instead of a lump sum payment after the end of the year. You need to pay advance tax, if your estimated total tax liability [after TDS] is Rs 10,000 or more in a financial year.
These payments have to be made in instalments as per due dates provided by the income tax department.
Advance tax applies to all taxpayers irrespective of the profession, whether you are salaried, freelancer, or businessmen. However, Senior citizens, who are 60 years or more , and do not run a business, are exempt from paying advance tax.
How to pay advance tax: https://blog.tax2win.in/online-income-tax-payment-guide