Sender ID is the identity through which the message is sent. It is the name with which your outgoing SMS will be sent. For example, when any general SMS appears in our mobile, their name or number will be displayed. Similarly when the message arrives from a company or brand which has a registered Sender ID it looks like the image below.

Sender ID for Promotional SMS is numeric and is decided by the operator. For example 658691

Sender ID for Transactional SMS is 6 alphabetic characters in India. For example: TxTAPI, SMSAPI, TESTIN, ABCDEF.