Is there a way to do number format in a fillable form?

If you use legacy Forms Fields, you can give a TextBox field a number format. Please follow these steps:

1. If the Developer tab is not visible, please choose FILE>Options>Customize Ribbon. On the right-hand list under Customize the Ribbon, check Developer. OK Out.
2. On the Developer tab, look for the Controls group. 
3. Click on the Legacy Tools icon (looks like a grey toolbox).
4. In the Legacy Forms row, choose the first icon Text Form Field. A textbox field is inserted in your document.
5. Right-click on the textbox field and choose Properties.
6. Change Type from Regular text to Number.
7. In the Number format dropdown, see if there is a format that meets your needs and pick it. Otherwise you can make a custom format by following the examples in the dropdown. OK out.
8. Legacy Form Fields must be in a protected document to work correctly. Choose Developer>Restrict Editing.
9. Under Editing restrictions, check Allow only this type of editing in the document.
10. In the dropdown below, choose Filling in forms.
11. Click on Yes, Start Enforcing Protection. 
12. Save your document and test whether the number format is correct in the form field when you type in numbers.