Making a Form Read-Only
The preceding section showed you how to disable the submit button after it is clicked once. That prevents the same form from being submitted multiple times. The same technique can be used to make all or part of a form read-only after it is first submitted.
For example, to prevent further changes to the Request Number field after the form is submitted:
Double-click on the Request Number field at the top of the form template. InfoPath displays the Text Box Properties dialog box.
Click Display → Conditional Formatting → Add. InfoPath displays the Conditional Format dialog box.
Complete the dialog box, as shown in Figure 10-12, to make the field read-only when DisableSubmit is selected.
Click OK three times to close the dialog boxes.
Preview the form to test the change.

Figure 10-12. Making a field read-only after the form is submitted
You can't apply conditional formatting to more than one control at a time, so if you need to make an entire form read-only, you'll need to repeat this procedure for each control.