It was already added before you noticed it. It should be automatically added as soon as you entered your W2 or income and qualify. Going though the earned income credit section just tells you how much you got.
The EIC is a refundable credit. It is included in your refund or reduced a tax due. Check 1040 line 18a for the EIC. EIC Info
https://ttlc.intuit.com/community/credits-and-deductions/help/how-does-the-earned-income-credit-or-e...
