Notepad++ - Add text at the start of every line

• Place cursor in the first line of the file to ensure all lines are affected
• Press Ctrl+H to bring up the Find/Replace Dialog
• Choose the Regular expression option near the bottom of the dialog
• Type ^ in the Find what textbox
• Type <text> in the Replace with textbox

Notepad++ - Add text to the end of every line

• Place cursor in the first line of the file to ensure all lines are affected
• Click Replace All button
• Type $ in the Find what textbox
• Type <text> in the Replace with textbox
• Click Replace All button