CloudFormation Template Validation Method

Can the CloudFormation template be changed to do the DNS validation for the provisioning certificate instead of email validation?
Because we don’t have administrator emails set up properly, but the domain DNS records are managed by AWS so this would be much easier for us.

It looks like you are referring to this tutorial. You can download the existing template provided in the tutorial, edit it to update the validation method and then upload and use the edited template. Here is the change you have to make:

In the template

"RootCertificate": {            
  "Properties": {                
    "DomainName": {                    
      "Ref": "Domain"                
    }            
  },            
  "Type": "AWS::CertificateManager::Certificate"        
  },

should change to

"RootCertificate": {            
  "Properties": {                
    "DomainName": {                    
      "Ref": "Domain"                
    },                
    "ValidationMethod": "DNS"            
    },            
  "Type": "AWS::CertificateManager::Certificate"        
  },