Explanation
Dynamic actions are a declarative way to define client-side behavior without writing JavaScript code. You can create dynamic actions on an item, button, or region of a page by specifying the event, condition, affected elements, action, and other properties. Some of the statements that are true about creating and using dynamic actions are:
You can execute JavaScript code by creating a dynamic action. One of the supported action types is Execute JavaScript Code, which allows you to enter custom JavaScript code to run when the dynamic action fires.
If a client-side condition is defined, the true action will fire when the condition is met, and the false action will fire when it is not. You can define a client-side condition for a dynamic action to control when it should fire based on an expression or value. You can also define different actions for the true and false branches of the condition. You can add additional true actions to a dynamic action by clicking the Add True Action button in the Property Editor. If no client-side condition is defined, true actions will fire when the event occurs. Verified References: [Oracle Application Express 18: Creating Dynamic Actions], [Dynamic Action Enhancements in APEX 21.1 - Oracle Blogs]

Explanation
Search configuration is a shared component that defines the data source to be searched and the way results should be displayed. You can create a search configuration based on a local data source (table or SQL query), an APEX list, a REST enabled SQL service, or a REST data source2. You can use one or more search configurations in a search page, depending on the search type you select. For example, you can use multiple search configurations for a standard search, but only one search configuration for an Oracle TEXT or a list search2.

Explanation
Open Door Credentials is an authentication scheme that allows anyone to access your application using a built-in login page that captures a user name. You can use this scheme for testing purposes or for applications that do not require secure authentication. You can select this scheme from the Authentication Type list when creating or editing an authentication scheme. References: [Understanding Authentication] and [Creating an Authentication Scheme]