301 redirect
snippet in php

301 redirect

user6210

301, "Moved Permanently"—recommended for SEO
302, "Found" or "Moved Temporarily"
Meta Refresh 

301 redirect

user4948

#In .htaccess
  
Redirect 301 /old-page https://www.example.com/new-page

301 redirect

user5898

#http to https and www to non-www
RewriteEngine On
RewriteCond %{HTTPS} off [OR]
RewriteCond %{HTTP_HOST} ^www\. [NC]
RewriteCond %{HTTP_HOST} ^(?:www\.)?(.+)$ [NC]
RewriteRule ^ https://%1%{REQUEST_URI} [L,NE,R=301]