In your mail-server, create a user e-mail account to which all e-mails will be fetched.
Create an e-mail alias for this e-mail account for each of your customer accounts.
Go to Admin -> Accounts -> Drill-down an account -> Enter the corresponding mail alias in the ‘support e-mail address’ field. This is the address to which the requesters from an account will send their e-mail requests. Eg: email@example.com
Once a requester sends a mail, ServiceDesk Plus – MSP will fetch emails at regular intervals from your e-mail account and automatically convert them into tickets for the corresponding account.