Sometimes you purchase a domain and hosting at truehost with the email of hosting your emails but hosting the website in another.

Normally, once you change the A records of a domain, the mx records automatically changes to where the A records are.

So how do you host your emails at truehost and the site elsewhere?

Login to whm> edit dns zone and select the domain name you want to host

Login to cpanel  of your domain>domains>zone Editor

Under the A records, you will see the A records created with the Truehost IP address

Now create the mx records with the A records you have created.