Redirect old domain to new domain and all pages within it, using htaccess file.

.htaccess

# BEGIN DOMAIN REDIRECT 301 TOWARDS newdomain.com
# ADD THE CODE WITHIN YOUR OLDDOMAIN.COM
# MODIFY THE www TO YOUR SPECIFIED SUBDOMAIN
# IF YOU ARE USING A NAKED DOMAIN, THEN REMOVE !^www\.
# IF YOUR NEWDOMAIN RESOLVES TO ANOTHER SUBDOMAIN
# THEN USE THAT NEW SUBDOMAIN INSTEAD OF www.
RewriteEngine on
RewriteCond %{HTTP_HOST} !^www\.newdomain\.com
RewriteRule (.*) https://www.newdomain\.com/$1 [R=301,L]
# USEFUL FOR:
# GOOGLE SEARCH CONSOLE - CHANGE OF ADDRESS
# END DOMAIN REDIRECT 301 TOWARDS NEW DOMAIN