I don't recommend old domain redirect to new domain in the domain registrar. You should host the domain in your website host, then use a simple .htaccess file to redirect all traffic on the old domain to the new domain.
<code>**Options +FollowSymLinks**
**RewriteEngine On
RewriteBase /
RewriteCond %{HTTP_HOST} ^OLDDOMAIN\.com$ [NC]
RewriteRule ^(.*)$ http://NEWDOMAIN.com [R=301,L]**</code>
Use your favorite text to like Notepad++ to create a .htaccess file and add the fire above. Make sure you replaced the domain name with your old and new domains respectively.
Then upload it to you old domain's hosting root folder (public html folder)
If you do it that way every click from the search engine to your old domain will always be redirected to the new domain.
Lastly, you will also need to add both domains to google search console and use the change domain tool to let google know about the redirect.
Adam Chronister recently conducted a simple experiment on this issue and he started seeing positive effects almost instantly.
I have used it on many of my websites and it's working perfectly well.
