One of the problems many users experience, is Word making changes within the text which they did not expect. (e.g. we type "6 March 2016", and it becomes, "6 March 2016-03-21")
We cannot re-write the Word manual here, but the following may help to point you towards making some helpful changes.
When you select Word's Options, and choose Proofing, you will be presented with the following screen:
If you now select the "AutoCorrect Options…" button, a dialog will be displayed which has multiple "tabs" to present different areas where "auto correction" may be applied.
Select the "AutoFormat" Tab. If you have ever wondered why things like Smart Quotes suddenly appear in your document, the "Replace" section of the following screen will explain why.
Now select the "AutoCorrect" tab. You may wish to select or deselect certain automatic actions on this tab according to your needs.
The "AutoFormat As You Type" tab holds still more options, including another action that introduces "smart quotes":
Please refer to your Word for Windows manual for full details of these functions.