Canonical Name or CNAME records are used mainly to connect domain names to websites, but can be relevant for email or security/verification records as well. CNAME records typically handle the setup of subdomains for your domain name, which would be addresses like www.mydomain.com or blog.mydomain.com. CNAME records cannot be set up directly for a naked or root domain.
It is common for a website hosting DNS records to include a CNAME record and an A record. That ensures visitors can access your website using the www version or the root/naked domain. The service or platform with which you're setting up your domain name should provide the specific CNAME and other DNS records you need to add in your Internetbs dashboard.
CNAME records can sometimes also be used for added security or to verify your account ownership. Google Workspace or Zoho Mail offer this option, for example. When setting up your email hosting, you create the CNAME record using a unique code you get from your email hosting account, which that account can then detect to confirm that you are the domain owner.