How to force the existing wordpress pages to use HTTPS SSL connection via plugin

Step 1: Log in to your WordPress site as the administrator.
Step 2: In the left-hand pane, click ‘Add New’ under the Plugins menu.
Step 4: In the Search text box, click Search Plugins.
Step 5: In the Name column, search and locate the plugin ‘WordPress HTTPS (SSL)’, and then click Install Now.
Step 6: After WordPress finishes installing the plugin, click Activate Plugin.
Step 7: Once the plugin activated, Navigate in to that and check on the force SSL for all pages to make your site secure