Mass Case Close button in Salesforce Lightning

 Mass close button is available only in salesforce classic. currently its not available in lightning.

To add the Mass close button in salesforce lightning list view, below are the steps 

1. Go to Setup and click on Object Manager.

2. Click on Buttons,links and Action in case object and click on "New Action"

3. Choose Action type as "Update a Record ", add Label, Name and success Message.

4. Click Save. It will take you to the pagelayout. Add the necessary field in the layout like below. I have added only 2 fields.

5. Click save and add the action to the list view. Under Case -> Search Layout for classic -> Click Edit on the list view layout.

6. Under   List View Action in Lightning Experience add the close button like below.

7. The button will be displayed in the list view. Choose  the multiple record and click on the "Close Case" button, it will appear as below.

Note: This button will not be visible in "Recently Viewed" list view.

8. Click Save. All the selected records are updated as closed.