The following code works as far as attaching a visualforce pdf and emailing it to who I want.  

What I need help with is that I would like to build a regular HTML email template and call it from my code.

Anyone that contributes will get kudos.

Here is the code:

 public PageReference emailPDF() {
 
     
    List<Contract> ContractToUpdate = new List<Contract>();
    
    for(Contract c : [Select Id, Invoice_Sent__c from Contract where Id =:ParentId])
    {
            c.Invoice_Sent__c = True;
            ContractToUpdate.add(c);
    }

    update ContractToUpdate;
    
 
     ToAddresses = new List <String>();
     ToAddresses.add(cc.Finance_Contact_Email__c);
     
     Subject = 'Hope this works';
     Body = 'This is a test';
 
 
     Messaging.SingleEmailMessage email = new Messaging.SingleEmailMessage();
     PageReference pdf = Page.ContractPDFCreation;
     pdf.getParameters().put('id',parentId); 
     pdf.setRedirect(true);
     
     Blob b; 

        b = pdf.getContent();

      
     Messaging.EmailFileAttachment efa = new Messaging.EmailFileAttachment();
     efa.setFileName('Invoice.pdf');
     efa.setBody(b);
  
     email.setSubject( subject );
     email.setToAddresses( ToAddresses );
     email.setPlainTextBody( body );
     
     email.setFileAttachments(new Messaging.EmailFileAttachment[] {efa}); 
     
     Messaging.SendEmailResult [] r = 
     Messaging.sendEmail(new Messaging.SingleEmailMessage[] {email}); 
    
     return new PageReference('/'+parentId); 
}

 Thank you,

Steve Laycock