Message Types: You can send the following types of SMS messages.
Promotional – Noncritical messages, such as marketing messages.
Transactional – Critical messages that support customer transactions, such as one-time passcodes (OTP).
An SMS can contain up to 160 GSM characters. If you send a big message, every 160 characters or part thereof is billed as a separate SMS. A single message cannot have than 1600 characters (i.e. 10 SMS's). However it is recommended to keep your SMS as short as possible for reliable delivery.
Sender ID: This is a name that appears as the message sender on recipients' devices. Sender IDs are a useful way to identify yourself to the recipients of your messages. For countries and regions that support Sender IDs, see Supported Regions and Countries. You need to request AWS to allot a Sender ID to you. More details here.
SMS Pricing: AWS SMS pricing is probably the lowest you can get. Pricing varies from country to country. See pricing information here.
Monthly Spending Limit: AWS limits the amount that you can spend to send SMS messages. By default, the limit is set to 1.00 (One) USD per month to prevent abuse or misuse. You can request a spending limit increase through the AWS Support Center. Follow instructions here.