I am not a tax specialist so I don't trust myself to explain in my own terms. The definitions below are Taken directly from Nerdwallet.com: "Both reduce your tax bill, but in very different ways.

Tax credits directly reduce the amount of tax you owe, giving you a dollar-for-dollar reduction of your tax liability. A tax credit valued at $1,000, for instance, lowers your tax bill by the corresponding $1,000.

Tax deductions, on the other hand, reduce how much of your income is subject to taxes. Deductions lower your taxable income by the percentage of your highest federal income tax bracket. So if you fall into the 22% tax bracket, a $1,000 deduction saves you $220."