If you're working a lot with websites, you need to stick with standard ASCII characters so that they can be displayed properly on the site.
By default macOS uses 'smart quotes' in order to make the quotes look better in a document but these can cause problems if you try to copy and paste the text into a website CMS.
Luckily, it's very easy to turn off smart quotes so that you use standard ASCII characters instead.
The first step is to open System Preferences by clicking on the Apple Menu and then System Preferences.
Once System Preferences is open, click on the Keyboard icon.
Now ensure that the box to use smart quotes and dashes is unticked. This will then produce text that you can copy and paste into your CMS without any problems.
Word on Windows does something similar and can cause the same problems, in order to turn of smart quotes in Word, follow the steps below.
Firstly, open Word and then click on the File menu.
Now click on the Options link down the left hand side.
Once you've done this, click on the Proofing section down the left hand side and then click on AutoCorrect Options.
You'll now see a new window appear, click on the AutoFormat as you type tab and untick straight quotes with smart quotes. Word will now use standard ASCII quotes that you can paste into a CMS.