Adding the Widget to page layout in Salesforce Classic

Once created, follow the steps below to display the widget in Salesforce Classic.

1. Open the object layout page in the setup and click edit.
2. Create a new section in the object layout.
3. Select the Visualforce page from the components option. 

4. Drag the Own page to the new section.

5. Click the Visualforce page properties button and set the ‘Height’ to 400 and enable the ‘Show scrollbars’ option.

6. Save the page layout.