Before we go in to depth about using the custom fields, it is important to know what custom fields are. Custom Fields are the section, for which you will have to scroll a little bit to find in page/ post edit section, that are used to input data, for example dimensions, weights, Client name, company etc. which is related to your post/page. To simply put it, it is a storage room for the data related to the post or page.
Sometimes the custom fields might not be visible. To make it visible, go to Screen Options and check the Custom fields.
Now, to using the customs fields, enter the name of the custom field you want to define in “Name” meta box.
Then, enter the value for that custom field in “Value” meta box and click on “Add Custom Field” button. The box flashes to yellow which means the custom field you have just created, has been saved.
We will be learning about how to display the custom fields in next tutorial.