According to TRAI, all application to people SMSes should be sent from a Sender-ID rather than a number. SMS Sender ID is the name with which your outgoing transactional SMS will be sent. Sender ID is a fantastic way to remind your customer of your brand name, so you should take full advantage of it.
Do not choose commonly used English words or phrases like "COFFEE" or "SMSFORU"
Do not use other company names or brands like "AIRTEL" or "LENOVO"
Do not violate someone else's trademark
- Avoid using numbers unless it is necessary (as it looks spammy). For ex: Avoid "BUY431".
It must be 6 characters long (mandated by TRAI. Don't ask us why)
It is always capitalized
It must be reflective of your brand name and/or trademark.
It must tie in well with the content in the SMS. It could be campaign specifc (See "How to change Sender ID")
Exotel reserves the right to reject your Sender-ID request if it finds it does not comply to these Dos and Don'ts. Having said that, we are here to make it easy for you send your SMS, so we will give you our reasons and suggest alternatives.
Also See How long does it take to approve a Sender ID.