I opened a Traditional IRA account in 2018. How do I let IRS know about my contribution when I file 2018 tax return ?

To enter your traditional IRA contribution:

1. On the left side of your screen, click Federal.
2. At the top of your screen choose Deductions and Credits.
3. Scroll down to Retirement and Investments.
4. Click Start on Traditional and Roth IRA Contributions.
5. Check that you contributed to a traditional IRA, and follow the rest of the prompts.