Hello Shariq,
Regardless of what kind of action you’re going to create, the first thing you need to determine is whether it should be object-specific or global. This decision should be based on whether you need your action to be explicitly tied to an object, and where you want the action to display.
Let’s go over the differences.
Object-Specific Actions
You create object-specific actions in the context of the object. From the management settings for the object for which you want to create an action, go to Buttons, Links, and Actions. You can add an object-specific action only to page layouts for that object.
There are five types of object-specific actions.Object-specific create actions create records that are automatically associated with related records. For example, you add an object-specific action on the Account object that creates contacts. If a user creates a contact with that action on the detail page for the Acme account, that new contact is automatically associated with Acme.
Object-specific update actions make it easy for users to edit records. You can define the fields that are available for update.
Object-specific Log a Call actions let users enter notes about calls, meetings, or other interactions that are related to a specific record.
Object-specific custom actions invoke Lightning components, Visualforce pages, or canvas apps that let users interact with or create records that have a relationship to an object record. The Visualforce page for an object-specific custom action must include the standard controller for the relevant object. For example, use the standard contact controller to create a custom action that lets users import a contact’s Twitter profile and add that information to a contact record.
Send email actions, available only on cases, give users access to a simplified version of the Case Feed Email action on Salesforce1.
Global Actions
You create global actions in a different place in Setup than you create object-specific actions. To create a global action, from Setup, enter Actions in the Quick Find box, then select Global Actions. They’re called global actions because they can be put anywhere actions are supported.
Global create actions enable users to create object records, but the new record has no relationship with other records.
Add Log a Call actions to global layouts to let users record call details. For example, users can log calls from global pages in Salesforce Classic such as the Home page and the Chatter tab, or in Salesforce1 from the Feed or Groups pages. In Lightning Experience, Log a Call actions on global layouts display in the Global Actions menu.
Use a Visualforce page, Lightning component, or a canvas app to create global custom actions for tasks that don’t require users to use records that have a relationship to a specific object.