Line 8 is your standard deduction. If you are single and 65 or older that is your standard deduction.
2018 Standard Deductions:
Single $12,000 (+ $1600 65 or older)
Married Filing Separately $12,000 (+ $1300 65 or older)
Married Filing Jointly $24,000 (+ $1300 each spouse 65 or older)
Head of Household $18,000 (+ $1600 65 or older)
Look at line 8 of your Form 1040 to see your standard or itemized deductions.