# How to restrict input in a text field?

If you want to allow an input to only receive a certain number or text format, you can use regular expressions.

For example, let's say that you want your input to receive an ID number that is structured like this: “010.124.501-55”. If you don’t know how to write regular expressions, you can simply ask any AI bot to do this for you, [ChatGPT](https://chat.openai.com/) for example:

<figure><img src="https://3448227606-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-LQ08RFAKZvFADEiXKFy%2Fuploads%2FnUPHTYjWaoaGXDP9Z0Et%2F3st-aa.png?alt=media&#x26;token=8922109c-565e-403d-935f-cd50f56c48b1" alt=""><figcaption></figcaption></figure>

After you get your regular expression, you can input it in the validation field of your component. Click on the component in builder -> Display tab -> Validate -> Use Regular expression

<figure><img src="https://3448227606-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-LQ08RFAKZvFADEiXKFy%2Fuploads%2FyVEtvWnmdXXalZSgGqUc%2F3st-c.png?alt=media&#x26;token=726c9d3f-1ade-4962-8e06-1748fc9b55ae" alt=""><figcaption></figcaption></figure>

You can also mention your field format in the custom validation error field for easier understanding.<br>