To re-order SharePoint List items in New Item Form, follow the below steps,
Step 1
Go to the particular SharePoint list setting page.
Step 2
Scroll down to the bottom of the settings page, just above the views option, you will see the 'Column ordering' heading.
Step 3
Click on it and we can change the column ordering number as seen in the below picture.
Step 4
Once done, click 'OK', same order will be reflected in the New Item form.
In case you have any concerns or queries, feel free to reach out.