STEP 1 : Login to cPanel ( Guide here )
STEP 2 : Navigate to Domains -> Zone Editor
STEP 3 : Click on + MX RECORD beside the domain you want to setup
STEP 4 : Set the priority and destination based on the Mail server you wish to use like shown below ( Examples are GSUITE and ZOHOMAIL )
STEP 5 : Click on Add MX Record after filling up the priority and destination values
Repeat steps 3-5 until all the MX Records are added.
STEP 6 : Delete previously configured MX record entries. (optional, if you've previously configured other MX records for the domain).
First navigate to Domains -> Zone Editor
Click on Manage beside the domain
Filter by MX Record
Delete any entry that is not related to GSUITE/Zohomail/custom mail server like below
After clicking delete, confirm the deletion like below
Please delete all the MX records unrelated to gsuite/zohomail/custom mail server
Please wait for 1-24 hours for the MX records to propogate and you can start using your GSUITE/ZOHOMAIL/Custom mail server