Step 1: Log in to cPanel.
Step 2: In the FILE section of cpanel there is one option for File Manager, click file manager.
Step 3: Go to the Public_html directory and find the .htaccess file.
Step 4: Paste below code in .htaccess file.
RewriteEngine On
RewriteCond %{HTTP:X-Forwarded-Proto} !https
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI} [R=301,L]
Step 5: Click on save Changes.