App passwords help you sign in to your Google Account on older apps and services that don’t support modern security standards. App passwords are less secure than using up-to-date apps and services that use modern security standards. Before you create an app password, you should check to see if your app needs this in order to sign in. Learn more on Google about signing in with app passwords 

Using your Google Workspace Administrator account, you should create an app password for the site.

All steps are outlined on https://support.google.com/accounts/answer/185833?hl=en-GB

Overview:

1. Open https://myaccount.google.com/security with the account you are creating the app password for
2. Ensure 2 step auth is enabled
3. You have to search on the account view for 'app passwords' to get Google to show you the App Password page
4. Give it a name - 'X site' and CREATE
5. A pop up screen gives you a password for your site - copy this, and save it to use on your site
   1. Note from Google on How to use it
      Go to the settings for your Google Account in the application or device you are trying to set up. Replace your password with the 16-character password shown above. Just like your normal password, this app password grants complete access to your Google Account. You won't need to remember it, so don't write it down or share it with anyone.
6. Enter the email and app password on your ARD Softward CMS Admin > MAIL settings on your site. 

Once you have your information ready, you will need to enter the following information: 

1. Go to Administration > Settings > Mail
2. Change the Outgoing Server to SMTP
3. Enter the requested details
   • Host
     • smtp.gmail.com
   • Port (Encryption)
     • Gmail SMTP port Port 587
   • Encryption
     • Encrypt TSL/SSL
   • Username
     • Your mailbox address (for example, example@domain.com/gmail.com)
   • Password
     • App/mailbox password
     • NB Password - enter with spaces
   • From Name
     • Name to appear on outgoing emails FROM field
   • From Address
     • Email Address that is sending the email
4. Click Save
5. Click Test Settings
6. Response you would like to see is: Settings updated and test email sent successfully!
7. Check your mailbox also for a test email that will have sent if your details were successully entered.