If you unable to see SMS configuration option in BUSY, there must be these case you need to check:
Step 1 : If using Basic model of BUSY SMS option is not available. So, BUSY model must be standard or enterprise.
Step 2 : Sub user dont have rights to configue SMS format in BUSY, give them rights to configure SMS format in BUSY.
To configure SMS format in BUSY, you need to follow these steps :
Step 1 : Go to administration then configuration
Step 2 : Then SMS API configuration, configure new format of SMS.
Step 3 : Now send SMS.