Default Actions
Default actions are Global Actions that are available on the Salesforce desktop site or on the mobile app, and provide quick ways to create core sales or service records.
To see which actions are available, check out Global Actions from Setup | User Interface | Global Actions | Global Actions as shown in the following screenshot:
From this list, we can see that Salesforce brought us some prebuilt Global Actions that we can use from anywhere in the CRM to, for example, create a new lead or a new opportunity, to send new mail, or simply to quickly log a call (by creating a new Task record).
You can change the fields that are displayed using the Layout link (as we'll see when we'll talk about Quick Actions), and from Setup | User Interface | Global Actions | Publisher Layouts, you can select which actions you want to expose, and to which user, by assigning different layouts depending on...