The Standard Deduction for Single is 12,200.  It is a good thing.    Everyone gets a Standard Deduction unless their Itemized deductions are more.  The Standard Deduction is subtracted from your income before the tax is calculated so you get taxed on a lower amount.  It means the first 12,200 of income is not taxed.

where are you seeing $1,200?

Taxpayers who can be claimed as dependents on someone else's tax return have a different standard deduction.   As of 2019, your standard deduction is limited to either (1) $1,100 or (2) your earned income plus $350, whichever is more.