Unable to insert signature / Google Doc table into script to draft emails

Question

I'm using a template that allows me to automatically draft emails to send. I'm using a Google Sheet and Google Doc to make this happen. The script is working fine, but I'm unable to insert my signature. I've tried various workarounds and have been unsuccessful. I have even tried to manually add the signature to the drafted email, but it will not allow it. I have created a table on my Google doc in an attempt to make this happen.

Is there any way to 1- add my signature to the drafted email? Or 2- insert the table from the Google doc to the draft?

Here is the code I'm using.

var googleDocId = "15mR-cuM9JVRwzXByd7-X8n_QgKODybdjXZJhyNYxW4c";
var emailField = 'Email';0
var emailSubject = 'Question About Your Business';
var emailStatus = 'Date Drafted';


var sheet = SpreadsheetApp.getActiveSheet(); 

function draftMyEmails() {
  var emailTemplate = DocumentApp.openById(googleDocId).getText();
  var data = getCols(2, sheet.getLastRow() - 1);
  var myVars = getCols(1, 1)[0];
  var draftedRow = myVars.indexOf(emailStatus) + 1;

 
  data.forEach(function(row, index){
    var config = createConfig(myVars, row);    
    
    
    // Prevent from drafing duplicates and from drafting emails without a recipient
    if (config[emailStatus] === '' && config[emailField]) {  
      var emailBody = replaceTemplateVars(emailTemplate, config);
      var emailSubjectUpdated = replaceTemplateVars(emailSubject, config); 
      
     
      GmailApp.createDraft(
        config[emailField],   // Recipient
        emailSubjectUpdated,  // Subject
        emailBody             // Body
      );
      
      sheet.getRange(2 + index, draftedRow).setValue(new Date()); // Update the last column
      SpreadsheetApp.flush(); // Make sure the last cell is updated right away
    }
  });
}

function replaceTemplateVars(string, config) {
  return string.replace(/{[^{}]+}/g, function(key){
    return config[key.replace(/[{}]+/g, "")] || "";
  });
}

function createConfig(myVars, row) {
  return myVars.reduce(function(obj, myVar, index) {
    obj[myVar] = row[index];
    return obj;
  }, {});
}

function getCols(startRow, numRows) {
  var lastColumn = sheet.getLastColumn();      // Last column
  var dataRange = sheet.getRange(startRow, 1, numRows, lastColumn) // Fetch the data range of the active sheet
  return dataRange.getValues();            // Fetch values for each row in the range
}