Hi ​@jpacheco,

I just wanted to clarify a couple of things to help ensure you get the best support possible. Your post appears in the Nintex for SharePoint (on-premises) forum, but you've also tagged SharePoint Online (O365). Additionally, the screenshot only shows a small portion of a form field, which makes it a bit tricky to understand the full context.

If you could confirm which Nintex product you're using and provide a bit more detail, that would really help the community assist you more effectively. We’re keen to help—just need a little more info to point you in the right direction!

The easiest way to remove the comma from a number field is to use a text field instead. You can use a regular expression as input validation to make sure that only a number can be entered.

​@SimonMuntz ,

So I’m using Nintex Responsive forms. I am using a text field but numbers will be the only thing entered in. A user that uses this form continues to input text, so I went ahead and applied a regular expression (as you suggested) which provides a message (to only input numbers) but how do you stop the user from moving forward and past that field as it only provides a message?

Hi ​@jpacheco,

I have moved this post from Nintex for SharePoint, which is for on-premise, to Nintex for Office 365, as it appears that is the product you are using.  It also appears that you are using a New Responsive form.
If you make the field required, as shown in the screenshot in your initial post, the user cannot simply skip past the field.  The field must contain a number before the form can be submitted.