where do i put all my redirects code example

Example 1: 301 redirect

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

Example 2: 301 redirect

#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]