When typing Word documents some people prefer to put two spaces after a full stop (like this). Some people prefer just one (like this). There seems to be no right or wrong way (I’ve looked), although single spacing seems to be agreed on as the modern way of doing things. Your choice will probably depend on how you learned to type, your organisation’s house-style and personal preference. Personally I prefer single spacing as I believe it looks neater, but each to their own.
The problem comes when spacing is not consistent throughout a document. The variation can look messy and might be distracting for the reader. To ensure your document looks professional take the time to make all of the spacing the same. This can be done quickly using the ‘Replace’ function in Word.