> For the complete documentation index, see [llms.txt](https://docs.goaffpro.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.goaffpro.com/affiliate-portal-customization/signup-page/additional-signup-fields-for-signup-page/setup-signup-field-with-input-mask.md). # Setup Signup Field with Input Mask **GoAffPro** provides you with the option to set up a signup field with an input mask. To set up a signup field with an input mask, go to the **Signup page** section in the **Look and Feel** tab of the GoAffPro admin panel.

Here, click on **Select & Customize**.

This will open up the signup page section.

Here, click on **Add your own field**.

This will open up the signup field window.

Here, set the field title.

Next, set the input mask. {% hint style="info" %} The input mask can be used to restrict what can be entered in the signup field. \ \ The number 9 represents all the digits from 0 to 9. \ The letter "a" represents all the letters from a to z.
**Examples:** If you want to set the input mask for US SSN (format: 3 digits - 2 digits - 4 digits), then you will set up the input mask as 999-99-9999\ \ If you want to set the input mask for PAN number (format: four letters, four digits, and one letter, like ABCD1234E or KLMN9983B), you will set up the input mask as aaaa9999a
{% endhint %}

Now, click on **Add**.

Next, click on **Save**.

Finally, the signup field with the input mask will be added to the signup page of the affiliate portal.

The signup field with input mask will get added

The input mask will restrict on what can get entered into this signup field.

{% embed url="" %} Setup Signup Field with Input Mask {% endembed %}