First, you need SSL Enabled on your Hosting.
Next, follow these steps to enable SSL on WordPress.
Step 1. Install Really Simple SSL plugin
Step 2. Activate Really Simple SSL
Step 3. Click on “Go ahead, actiave SSL!”
If Your hosting has enabled SSL Certificates, you will see the blue message as shown below
If Your hosting is not enabled SSL Certificates, please check again
Step 4. You need to log back in order for SSL to be updated
To SSL testing, you can check it out at: Whynopadlock.com