I believe you are referring to the new Standard Deduction amounts. $24,000 is the Standard Deduction if you are Married Filing Jointly.  The Standard Deduction is listed on Line 8 of your Form 1040, unless you use Itemized Deductions from Schedule A instead.

The Tax Cuts and Jobs Act (TCJA) that Congress signed into law on December 22, 2017, increased the Standard Deduction to the following amounts based on your filing status:

• Single/Married File Separate- $12,000
• Head of Household- $18,000
• Married Filing Joint- $24,000