Add an SMS block and fill Name, Sms number from (one of your active SMS numbers) and Content. The content box supports Shortkeys personalisation, shows a character/segment counter and warns Note: Special Non-GSM Characters Increases Rate. (ñ, à, ö, -, , ~)*. A Utm tracking section is also available. The message goes to the customer's phone number and is charged from your SMS credits per segment.

The block appears greyed out with a Disabled badge (hover for the reasons) when:
- You don't have phone numbers available! – no active SMS number on the account, or
- You need to comply with US A2P 10DLC Regulations! – for US accounts the SMS campaign registration is not complete.

SMS steps also skip customers whose Receive SMS setting is off, and stop if your SMS plan limit is reached. A one-time pop-up (Did you know you can send a text message (SMS) in these flows?) introduces the feature.