Label-When php does not submit a new form, how does one modify the label value on the original page?

In the original page index.html, you can use this method to submit a new form without any need. In index.html, when a labelfile is submitted, the actionpage is form.php. if you want to set the label value in index.html to "submitted successfully" in form.php, how can this problem be achieved? Tag php form

In the original page index.html, you can use this method to submit a new form without any need.
In index.html, there is a label
The action page for submission is form. php.
When the submission is successful, set the label value in index.html to "submitted successfully" in form.php ",

How can this be achieved?