Where is the 6300.00$ coming from? what is it

[Anita01]

If you are filing as a single person or as married filing separately, $6300 would be your standard deduction.  That's an amount of income you are able to earn before you start owing tax. Essentially, if you earned $20,000. say, in wages on a W-2, you would only owe tax on $20,000-$6,300.  It's not an amount you get back in tax, it's an amount that lowers your taxable income.