When entering text into a document, MS Word wraps your text onto different lines for you. This is expected and very useful, but can cause problems when you do not want a word to be broken over different lines in a document.
Examples of this may be when entering text such as 20 kg, or a customer reference code like AD TYH 3506.
To prevent a word from being broken across different lines you need to insert a non-breaking space in Word instead of a traditional space.