You can manually force HTTP to HTTPS after enabling your SSL certificate by adding the following condition at the beginning of your .htaccess file in your public directory:

RewriteCond %{HTTP:X-Forward-Proto} !=https
RewriteRule .* https://%{HTTP_HOST}%{REQUEST_URI} [R=301,L]

Save your file and restart your Apache server and now, your web application will redirect all your users to https:// instead of http:// URLs in the future.