Publisher Actions do not appear on the Chatter or Home tab

There are two scenarios in which this will occur:

​​​​​​Scenario 1: The User object's publisher layout has been customized to display a different set of actions.

1. Navigate to Setup

2. Access Page Layout for the User object:

   1. From Salesforce Classic:

      1. Enter User in the Quick Find box

      2. Select Page Layouts below the User object

   2. From Lightning Experience

      1. Click Object Manager

      2. Click User

      3. Click User Page Layouts on the left

3. Edit the impacted page layout.

4. Click and drag the desired actions

   1. For Classic, click Quick Actions and drag the desired action into the Quick Actions in the Salesforce Classic Publisher section of the page.

   2. For Lightning Experience, click Mobile and Lightning Actions and drag the desired action into the Actions in the Salesforce Mobile and Lightning Experience Actions section of the page.

5. Click Save.

Scenario 2: A record type was added to the object after the Global Action for the same object was created.

If you check the User object's page layout and the action has already been added, the issue may be due to a recently added Record Type.

1. Navigate to Setup and type Global Actions into the Quick Find box

2. Click Edit next to the action in question

3. Check the Record Type box. 

   If the object associated with the action has at least one record type, the action must be set to something other than --Master--. 

4. Select a record type.

5. Save