What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
In this case, you can use the Mask value so you can set the required numbers to input on your mobile number field. Please follow the steps below.
1. Click the Phone number field.
2. Click Input Mask.
3. Then click Mask Value. Enter the preferred numbers, # is equivalent to 1 number. You can also use (-) to separate numbers.
4. Here is the sample form using Mask value.