If your administrator has enabled the option to edit form responses after submission, you can easily modify an existing submission by following these steps:
Navigate to the "Responses" tab.
Locate the specific submission you wish to edit, either by applying filters or using the title.
Re-open the submission, which will open it in read-only mode.
In the top right-hand corner, click on the "..." icon.
Select the "Edit" option and proceed to make the necessary changes.
After making the desired changes, click "Submit" to save the edited submission.