In order to force your web traffic to use HTTPS, edit the codes in the .htaccess file.
For information on how you can edit your .htaccess file click here.
To redirect all web traffic:
RewriteEngine On
RewriteCond %{SERVER_PORT} 80
RewriteRule ^(.*)$ https://www.YOUR-DOMAIN-HERE/$1 [R,L]
(Replace "Your-Domain-Here" text with your Domain Name)
To redirect traffic to a specific directory:
RewriteEngine On
RewriteCond %{SERVER_PORT} 80
RewriteCond %{REQUEST_URI} folder
RewriteRule ^(.*)$ https://www.YOUR-DOMAIN-HERE/YOUR-DIRECTORY-NAME-HERE/$1 [R,L]
(Replace "Your-Domain-Here" text with your Domain Name and "Your-Directory-Name-Here" with the name of your directory / sub folder)