Cold Email: When you send emails on your client's behalf, do you always create subdomains?

Hello everyone,

I was curious, whenever you send out emails for a new client from their dot com email, do you always create a subdomain for their email first?

Here's an example. Let's say you have a client and their website is theirwebsite.com

Let's say you create emails for them using G-Suite and your email is [marketing@theirwebsite.com](mailto:marketing@theirwebsite.com)

Before you send emails, do you create a subdomain for each of them to avoid potential blacklisting?

I learned about this by creating my own website and a friend's site. Is this a must for everyone here?

Cold Email