Monster Tools mail configuration is simple and easy. Navigate to Settings > Mail and click "Use SMPT" you will see SMTP options below simply enter your mail credentials.

Note: Once you save settings system will automatically clear cache and allow application to rebuild it but in case if your SMTP isn't working please go to Settings > Advance and click Clear Cache.
To create an email account:
Log into cPanel.
In the Email section, click Email Accounts.
In the Email field, type the name you want and select the domain name from the drop-down menu below. Note: The email name shadow is reserved and cannot be used for an email address.
In the Password fields, type the desired password twice.
Make a selection for Mailbox Quota.
Click Create Account.

The following steps will allow you to create new email accounts in Plesk:
Note: This example is using Plesk 17.8.11; however, the steps will be similar for other versions of Plesk.
Login to Plesk.
If using your admin login, under Hosting Services, select Domains and click the link to Manage in Customer Panel (Control Panel link).
Select Mail in the left-hand menu.
Click the Create Email Address button.
Enter a name for this Email address.
If more than one (1) domain is listed in the account, select the desired domain name from the drop-down.
Check the box to grant the email Access to the Customer Panel.
Create or generate a password for the email account.
Specify the mailbox size limit (25 MB is a good start) or opt to use the default size.
(Optional) Create a description for the email that will be visible to everyone who has access to that email account.
Click the OK button to finish.