You don't - it is added automatically if over age 65. The 1040 line 12 will show the standard deduction plus $1,300 if over age 65 for each spouse and there is a question in the personal information section that asks your date of birth and if you are blind.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
