Below are the step by step how to get your own Google Maps API Key

1. Go to - make sure you're log in with your google account.

2. Click "Get Started" button and it will showing popup for you to pick the product, create project and setup billing

3. Click the product you'd like to use then create project, having done that, click Next button

4. Once you click the Next button, you'll be redirected to Billing page, click "Create Billing Account" as shown on below image

5. Once clicked, choose your country, and accept the term and conditions

6. On the next page, you will need to fill in your billing details (address, contact and payment method), once done, click Start button and you'll be redirected to your Google Cloud Console page 

7. On console page, you'll see your project page that you created earlier. Now, you just need to create your API key through it. 

8. To generate the API key, you just need to click the top left menu, on API & Services menu choose Credentials

9. Once you clicked it, the API will be automatically generated for you as per below

10. From the dialog displaying the API key, select Restrict key to set a browser restriction on the API key 

11. In the restriction section, select HTTP referrers, then add your domain as referrer (note: https and http protocols are considered different URLs)

12. Press save and the API key now can be used for your website.