If you want to add a blank i.e. new line after each line in a text file, you can do it with Notepad++ find and replace option,
Go to Find and Replace
Search mode type : /n
Find what : /n
Replace with : /n/n
Select mode : Extended
1. Open text file in Notepad++
Load your text fine with Notepad++. Now press Ctrl+F to open Find and Replace box. Select the Replace box.
2. Find and Replace tab
Now, Select Select Mode : Extended , and in the Find field add /n and in Replace field add \n\n (i.e. two new lines characters to make one line break to two) and Click on Replace All button.
Now blank lines are added after each line to the text file.