What is an SMS Header?

The SMSHeader is a set of characters that either comprises alphabetic or numeric characters. It identifies the identity of a sms sender and operator information. Let's consider an example: when you receive a standard text message from a friend or family member, their name (as stored in your contacts) appears as the Sender. If you haven't saved the receiver's phone number, it will be shown instead.
The SMS Sender ID is a number or letters representing the company or brand name with operator information when a business or firm sends an SMS to its consumers. This Sender is given to the firm or organization for use in messaging to its clients.

Promotional Messages
The SMS Headers that may be utilized for sending Promotional communications are classified as PROMOTIONAL SMS. A commercial message can be sent to a mobile subscriber whose settings are not set (not on DND). Any commercial communication that an organization may send to a specific recipient after obtaining consent to do so.
Header (6 numeric): 565690, 787878, 987123, 555555, etc.

Transactional Messages:
The bank gives a text message containing One-Time-Password (OTP) and necessitates the completion of a banking transaction allowed by the customer. This covers all banks, including national/scheduled/private/Govt. and MNC banks. Customers are receiving these emails from businesses to assist and guide future interactions. These communications aren't commercial or promotional content; instead, they're intended to respond to the consumer's actions.

Service Implicit Messages:
Messages deriving from the customer's actions or relationship with the Sender that are not promotional and blocking such communications are not in the customer's best interests are service implicit messages. Even if a user has previously blocked service messages, these alerts will not be stopped for subscribers who have also blocked communication from services.

Service Explicit Messages:
Any service message that does not fall under the category of service message (Implicit) shall be issued only when the subscriber has given their explicit, digitally verified/verifiable approval to the particular organization These are called service explicit messages.