Using Subdomains with Wix
Subdomains are used to connect the same domain to resources on two different servers. For example, if you have a domain - www.domainexample.com - pointed to your Wix site, you may also want to create a subdomain - blog.yourdomain.com - which would point to where your blog is hosted.
To add a subdomain: Sign in to your Wix account > from the menu at the top, hover over Subscriptions > click Domains > click Use a Domain You Already Own > click Connect your domain to Wix but keep your current registrar.
Under Connecting your own domain, fill in the subdomain information, select the relevant site and select your registrar > click Next.
Once you have added the subdomain to your account, you will need to add the following DNS records for the primary domain.
A (Host) record for examplesubdomain.mydomain.com
CNAME (Aliases) record www.examplesubdomain.mydomain.com
CNAME (Aliases) record for m.examplesubdomain.mydomain.com
To add DNS records: Under My Domains, next to the relevant domain, click Manage.
Under Domain Summary, select the Advanced tab > next to DNS Records, click Manage > add or edit your records according to your requirements.