To edit the Submit button, go to the Form Editor of your form within the form builder and click on the Submit button area. Its Edit Field panel will open on the left side of the page.
There, you can change the alignment and the text displayed on the Submit button. You can also add Additional buttons, such as the Print or Reset button.
If you want to edit the submit button in terms of appearance, you can achieve this by going to the Design section.
Here you will find various customization options, such as changing the border, font, and color, just to name a few.