How to Get Etherscan API Key?

Steps

1. Visit Etherscan website

2. Click "Sign In" on the top-right corner

3. Login if you already have an account, or click "Sign Up" if you do not have an account

4. Once logged in, hover your mouse on your logged in username and click "API Keys"

5. Scroll down to see the "API Keys" panel and click "+Add"

6. Give a name to your API key (probably only you can see)

7. Copy and note down your API key for later

Additional Steps for Remix IDE

8. Get back to Remix IDE and click "Enable?"

9. Edit API key in Etherscan section and then click "Save"

10. Congratulations! you can now verify your deployed smart contracts