Carry out the following steps to edit an existing Home page to provide a system support email link using Lightning App Builder:

1. Click on the Setup gear icon, as shown in the following screenshot:

2. Click the Setup option, as shown in the following screenshot:

3. Type app builder in the Quick Find search box, as shown in the following screenshot:

4. Select the Lightning App Builder option.
5. Click the Edit link for the Home_Page_Default customized Home page, as shown in the following screenshot:

6. In the resulting Lightning App Builder page, drag and drop the Rich Text component from the standard Lightning Components pane to the top of the Home page canvas, as shown in the following screenshot:

7. Click on the newly added Rich Text component and enter For Salesforce Help please send requests for support to into the Rich Text properties section.

This is shown in the following screenshot:

8. Click the Link icon, as shown in the following screenshot:

9. Select E-mail, as shown in the following screenshot:

10. Enter the appropriate details for your organization in the E-Mail Address, Message Subject, and Message Body textboxes, as shown in the following screenshot:

11. Click on OK.
12. Choose the text font, size, and color using the text formatter, as shown in the following screenshot:

13. The Lightning App Builder page should now be configured, as shown in the following screenshot:

14. Click on Save.
15. Finally, click on Back.