It is automatic if you or spouse is 65+. You don’t need to do anything. It is calculated on 1040 Schedule 1-A. Which goes to 1040 line 13b. This is in addition to the Standard Deduction or Itemized Deductions on 1040 line 12e.
See this recent post with screenshots
https://ttlc.intuit.com/community/taxes/discussion/2025-senior-deduction-under-the-obbb/00/3716229
