Check out 301 redirect plugin
https://wordpress.org/plugins/simple-301-redirects/
OR
Add redirect rule in to .htaccess file
RewriteEngine on
RewriteCond %{HTTP_HOST} ^example.com [NC]
RewriteRule ^(.*)$ https://www.example.com/$1 [L,R=301,NC]
RewriteEngine On
RewriteCond %{HTTP:X-Forwarded-Proto} !https
RewriteRule ^(.*)$ https://%{HTTP_HOST}/$1 [R=301,L]