How to set-up your phone and post opt-in fields

If you’d like to collect the post and phone preferences of users completing your Impact Stack forms, this article can show you how. Companion articles that might also be of use include:

There are two special form field types for managing your users phone and post preferences of your users. They are called ‘Phone opt-on’ and ‘Post opt-in’ and you simply drag them onto your form in the usual way:


They are configured in the same way as eachother.

The fields offer a wide range of different options, so you have a lot of choice in how you manage these opt in fields. In this article we will focus on just a few scenarios for each type and show you how to set these up. We have focused on checkboxes as these are the most popular configuration for phone and post opt ins. But you could also use radios instead; the advantage of a radio is that you can allow the user to actively give an active positive answer, e.g. “Please send me post” or an active negative answer, e.g. “please don’t send me post”. This can be configured on the ‘display’ tab of the opt-in fields.

If you want to implement something different and aren’t sure how, we recommend dropping us an email at and we can guide you through your setup.

Please note: these scenarios are not legal recommendations, you must make legal decisions internally on how you wish to implement GDPR in your organisation.

Jump to the scenarios

But first, here’s an important note, regardless of your opt-in setup:

Collecting the opt-in statement for your records

On the ‘properties’ tab of the field, add the opt-in statement for the post/phone opt in. Impact Stack stores this text along with a log of when and where the user opted in/out, meaning you have a full record of what people opted into, and when. Read more about accessing this sign-up data.

You should put in the opt-in area the exact language you are showing to your users as they opt-in, e.g. “I would like to hear from charity Y by post”.

The contents of this field area isn’t displayed on the page. It needs to match the copy that you enter in the field title, a markup field above, or a combination, depending on your template and style preferences.


Scenario 1 - Phone opt-in using a checkbox

Here's how it might look to the user:


Set-up steps:

  1. Drag the phone opt-in field onto your form
  2. Update the label under the display tab, e.g. to ‘I consent to being contacted by phone’
  3. Don't forget to add your opt-in statement
  4. Save your form

Scenario 2 - collecting the phone opt-in with the number field

Within Impact Stack it is possible to configure your form so that when the user gives you their phone number they’re also opting in to give permission for you to use it. Of course it is critically important that if you use this feature that you make it really clear to the supporter that by giving their number they’re also consenting to be called. Here's how it might look to the user:


Set-up steps:

  1. Drag the phone number field onto the page
  2. Click on the green ‘configure’ pencil
  3. Toggle to ‘On’ the field ‘Giving a phone number implies a phone opt-in'
  4. Don't forget to add your opt-in statement
  5. Explain somewhere to users that giving their number is giving consent for you to use it. You can use the description field for this or a separate markup field depending on how you want it to look in your template
  6. Save your form

Scenario 3 - Post opt out by checking an empty checkbox

In this scenario:

  • The user will see a checkbox that’s empty by default, they can check it if they don’t want to receive post.
  • You are not collecting a post opt-in from anyone, just an opt-out

Here's how it will look to the user:

Set-up steps:

  1. Drag the post opt in field onto your form and click the green ‘configure’ pencil
  2. Navigate to the ‘display’ tab and choose ‘ inverted checkbox’ from the dropdown and add a label for your checkbox reflecting your chosen opt-out language


  3. Navigate back to the ‘Properties’ tab and change the default value to ‘no change’ (see below)
  4. Toggle ‘on’ ‘Interpret a checked inverted checkbox as opt-out’ (see below)
  5. Toggle to on ‘Only allow opt-out’ (see below)


  6. Don't forget to add your opt-in statement
  7. Save the form

As always if you require further support, please email

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