Everyone gets to take a Standard Deduction amount off their income before the tax is calculated (it's a good thing - it lowers your income). Unless their itemized deductions are more. Itemized deductions are things like Medical, Gifts to Charity, State Income Taxes Paid, Mortgage Interest, Property Taxes, Car Registration fees, etc.
For 2018 the Standard Deduction will be doubling so most people will be switching from itemizing.
For 2018 the standard deduction amounts are:
Single 12,000 + 1,600 for 65 and over or blind
HOH 18,000 + 1,600 for 65 and over or blind
Joint 24,000+ 1,300 for each 65 and over or blind
Married filing Separate 12,000 + 1,300 for 65 and over or blind
And see FAQ on many 2018 changes
https://ttlc.intuit.com/questions/4482394-how-will-tax-reform-affect-my-2018-federal-tax-return
