Tony Dong

You can insert widgets in Magento 2 using Content > Widgets interface or directly in content of the page, block or any editor which support widgets. When to use each method depends on the situation. More details about each method below.

The Custom Layout Update field on the CMS Page Edit, Category Edit, and Product Edit pages has been converted to a selector, in Magento starting version 2.3.4 to enhance security. You can no longer specify an entity-specific layout update with text but instead must create a physical file that contains the layout updates and select it for use. [...]