1. Open httpd-vhosts.conf (/opt/bitnami/apps/wordpress/conf/httpd-vhosts.conf) , it should look like this:

2. Add the HTTP to HTTPS redirect rule and configure VirtualHost for SSL Port (443), it should look like this:

3. Modify site url in wp-config.php (/opt/bitnami/apps/wordpress/htdocs/wp-config.php) from http to https: