Sales Invoice UI redesign

Can l redesign my sales invoice UI to look like this , where do l find the forms to redesign my invoice to look like this , have researched everywhere but cant find info. Anyone who can assist.

You’re not going to get anything like that with the standard form view, but you can create a custom page that can look like anything you want.

Ok thanks but have tired that and ended here

So that’s the code for the new page I have modified to accept custom content so according to the tutorial I’m suppose to add content on that line where its written “Let body=<h1></h1>” so after adding my html code it gives errors that I cannot add divs in that line