As a web professional, I have often come across clients who want to update their own website. That’s great because WordPress gives them the ability to do just that. Still, just because someone wants to update their website doesn’t mean they want to become a full-on developer. Frankly, there are some default behaviors inside WordPress that make things more difficult for non-technical users.
That’s where WordPress custom fields come in. In the hands of a savvy developer, custom fields can add all sorts of new content areas and functionality. For example, you might add WYSIWYG fields, fields to allow for file uploads, date pickers and so on.
You can find more about this here!
Image Source: http://marketblog.envato.com/tips/custom-fields-clients/