Global attributes can be created and managed via the "Attributes -> Global" tab of a product details page.
If speaking about global attributes, the primary purpose of the "Attributes -> Global" tab of a product details page is to give a store admin the tool to assign and configure global attributes for this particular product.
It's generally accepted that the respective global attributes are created beforehand via the "Classes & Attributes" section (Catalog > Classes & attributes), as described in the Creating Global Attributes guide. It is the most common way of global attributes management.
However, if there is a need, it's also possible to create a global attribute and assign it to a product directly in the "Attributes -> Global" tab of a product details page.
So all-in-all, the "Attributes -> Global" tab of a product details page gives a store admin the tools for creating, assigning, and managing global attributes directly on a product page. In addition, the changes to global attributes via the product details page can apply both store-wide and at the product level only.
Adding Global Attributes
It may turn that there is no required global attribute in the list of global attributes assigned to a product, or you may want to add another global attribute to the list. You can do it directly from the "Attributes -> Global" tab of any product details page.
To add a new global attribute:
In your store's Admin area, locate the product you need to assign a global attribute to, open the product details, and click on the "Attributes" tab.
Select "Global" in the drop-down.
Use the "Global attributes" section to add information about a new attribute.
To add a new global attribute to the list, click the" down arrow" part of the "Add attribute" button and select the type of attribute value you require (Plain field, Textarea, or Yes/No) from the drop-down button menu.
For an explanation of the different attribute value field types, see Attribute Value Field Types.
Use the "Attribute name" and "Attribute option" fields to specify the attribute name and option(s).
Choose whether you want to apply the changes you made locally or globally by enabling the Apply attribute value changes for all the products toggle.
When you apply attribute options globally, it affects only the existing products when you save the changes. Therefore, any products that you will create later will not get these values automatically.
If you want to automatically assign such a global attribute to all future products in your store, enable the check-mark icon for this attribute option, as described in Creating Global Attributes.
Click the "Save changes" button at the bottom of the screen.
Editing Global Attributes
To edit global attributes via the "Attributes -> Global" tab of a product details page:
In your store's Admin area, locate a product for editing, open the product details page, and click on the "Attributes" tab.
It can be any product with this attribute: you will be able to extend the changes store-wide.
In the "Attributes" drop-down, select "Global."
On the page that opens, locate the "Global attributes" page section.
To edit the values of global attribute options (the options that have been added automatically along with the global attribute assignment):
Click on the attribute option name to change it, or click on the drop-down arrow next to the attribute option name to choose an option from the suggested list.
For multivalue global attributes, click on the Modifiers link next to the attribute option name to add Price and Weight Modifiers.
In case "Modifiers" are added to the existing global attribute option(s) and are applied globally (with the "Apply attribute value changes for all the products" toggle enabled), the changes will affect only the products with the corresponding attribute option(s) active. All products that have the corresponding attribute option(s) disabled will stay as-is.
Specify whether you want to apply the changes globally by enabling the "Apply attribute value changes for all the products" toggle.
Click "Save changes."
Deleting Global Attributes
To delete a global attribute via the "Attributes -> Global" tab of a product details page:
In your store's Admin area, find any product with the global attribute you want to delete, open the product details page, and check the "Attributes" tab.
In the "Attributes" drop-down, click "Global."
On the page that opens, scroll down to the "Global attributes" section.
It does not matter whether the setting Apply attribute value changes for all the products is enabled or not: deleting global attribute on a product details page hides only this product's option.
To remove the attribute for all the products, use the Classes & Attributes page.
Click Save changes.