# SMS Distribution

## 📄 What is SMS distribution ?

Using the phone sms distribution features you can easily send out invitations to a list of mobile phone numbers who receive by SMS a uniquely generated code to take your survey. This unique code allows you also to restrict access to the survey and to track if the invited respondents have answered your survey or not.

{% hint style="info" %}
🧙  You may also replace the uniquely generated codes by any pre-generated code of your choice using the [token](https://docs.ngsurvey.com/form-management/security/security-items/tokens) features. 
{% endhint %}

 Mobile phone recipients can be added 

* [Manually entered mobile phone lists](https://docs.ngsurvey.com/form-management/campaigns/campaign/phone-sms-distribution/sms)
* [Imported using a CSV file](https://docs.ngsurvey.com/form-management/campaigns/campaign/email-distribution/recipients)
* [Using members of panel](https://docs.ngsurvey.com/form-management/campaigns/campaign/panels)

{% hint style="warning" %}
While automatically enabled during the campaign launch its important to note that the i[nvitation code security item](https://docs.ngsurvey.com/form-management/security/security-items/invitation-code) must be enabled on your survey to validate the invitation codes and to link the email to the respondent.
{% endhint %}

{% hint style="danger" %}
The mobile SMS phone feature requires to have a [Twilio.com](https://docs.ngsurvey.com/installation-setup/system-settings/mobile-messenging/twilio) account linked to your ngSurvey account.  
{% endhint %}