About copy and paste content and formatting

Paste the content in the visual mode and adjust the line spacing and save it.Avoid the spacing between the lines.

if you are pasting the content in editor mode use the html tags properly,avoid the like breaks and spacing between lines ,
use like these

<h4>Lorem ipsum dolor sit amet,<br/> consectetur adipiscing elit</h4>
<p>Lorem iscing elitLorem ipsum dolor sit amet consectetuadipiscingelitLorem ipsum dolor sit amet,</p>
<p>consectetur adipiscing elitLorem ipsum dolor sit amet,color sit amet,consectetur adipiscing elitLoreconsectetur adipiscing elit</p>