Promotional SMS: The term defines the SMS which are meant for promotion. The motive to advertise, promote or brand any service or a product. Regardless if the content is simple, it will be considered as a marketing sms service.
Transactional SMS: It is used by an organization, to send invoice details, inform about appointment status, to tell about purchase confirmation alerts, student progress information to their parents, status of bank account, OTP purpose and for many other softwares