On account record page, clicking on Actions dropdown menu will show you the View Account Hierarchy action. If you customized the Salesforce1 and Lightning Experience Actions of the account page layout before Spring ’17, add the action to your account page layout.
Read MoreAccount hierarchy gives the sales team an overview of the relationships between parent and child accounts. This feature is now available to Lightning Experience users with a plus point: Now you can customize hierarchy columns to show the details that are most useful to your sales teams. This change is available in Lightning Experience only. Account hierarchy is available in: Group, Professional, Enterprise, Performance, Unlimited, and Developer Editions.