How to configure subdomain for 'project email address' setting?

[IT]

Got stuck here after trying to Configure the DKIM records, apparently we're already using SendGrid to send emails from our domain for another service. 

So according to the documentation: In this case, it seems recommended that we use a subdomain for the 'Project Email Address' setting. For example, use Jira@notifications.company.com instead of Jira@company.com.

Q1, is there a workaround that we don't need to use subdomain?

Q2, how to configure subdomain for 'project email address' setting? 

[Deleted user]

So have the same problem but ended up using a subdomain instead.

We had to add the the SPF record and the DKIM for a subdomain on DNS. Here is a link on how to do it.

https://confluence.atlassian.com/adminjiracloud/configuring-jira-cloud-to-send-emails-on-behalf-of-your-domain-979428371.html