Create a custom action is the recommended solution to meet the requirement of creating additional accounts to form a hierarchy from a Parent Account record. According to the Salesforce documentation, "Actions let users quickly create or update records, log calls, send emails, and more, in the context of a particular object." A custom action can auto-populate fields based on the parent account and make it easier for users to create child accounts. Add Path on Account hierarchy, add a custom link on Account, and customize a Global Quick Action are not valid or feasible options.