Regulations
In the United States, the rules and regulations of the Telephone Consumer Protection Act (TCPA) and the guidelines of the Cellular Telecommunications Industry Association (CTIA) are the two primary frameworks that apply to SMS marketing. When sending SMS to a US phone number, you must follow the rules and guidelines set out by the TCPA and CTIA along with all other applicable laws and regulations.
In your messages, it is highly recommended that you include:
Your organization’s name or a way for recipients to easily identify your brand
Instructions on how to opt out from receiving future messages
You should not include any prohibited content in your SMS. If you do, carriers will likely filter your message, and it won't be delivered to your intended recipient. They may also filter future messages from your business regardless of content.
Consent
In the US, you must get express consent to send an SMS or MMS message to any US phone number. Express consent must be specific to SMS and cannot be inferred from consent or subscription to other marketing messages or channels.
SmartrMail enables you to collect consent from:
SmartrMail subscription forms
SmartrMail popups
Your checkout
List Uploads (coming soon)
Wherever you are collecting SMS consent, you must display some text clearly stating that individuals who sign up for SMS are consenting to receive text messages from your business. Not providing this type of disclaimer can result in fines. Note that the text must mention SMS in specific; saying that the subscriber is agreeing to receive marketing messages in general or email marketing is not good enough.
You must also update any relevant legal documents including your terms of service and privacy policy to detail how you will handle SMS consent.