I have created a list with some fields. The orignal form looks like this:
We can quickly customize this form. I will change the colors of this form and add an additional row in the bottom of this form. To do this Go to the List --> List Tools --> Customize Form
This will open the form into the InfoPath 2010 directly. We can just change the color like we can do in other Office Apps and save it. I just made the color purple and added one row with Static Text in the bottom. After that just did a Quick Publish and the form got published with the list. For this we dont need to do anything. Once the form is published it is looking like. All the form for the View, Edit and New are customized like this.