Two ways that an administrator can query Order Summaries using APIs in Workbench are:

Platform API. The Platform API is a set of REST and SOAP APIs that allow developers to access data and functionality in Salesforce from external systems. The Platform API includes various resources and operations for querying, creating, updating, or deleting records in Salesforce, such as Order Summaries. The administrator can use the Platform API in Workbench byselecting the REST Explorer or SOAP Explorer tabs, and entering the appropriate request URL and parameters.

Composite API. The Composite API is a type of REST API that allows developers to execute multiple subrequests in a single HTTP request. The Composite API includes various resources and operations for batching, tree, sObject collections, or transactions in Salesforce, such as Order Summaries. The administrator can use the Composite API in Workbench by selecting the REST Explorer tab, and entering theappropriate request URL and JSON body.

Verified References: https://developer.salesforce.com/docs/atlas.en-us.api_rest.meta/api_rest/intro_what_is_rest_api.htm https://developer.salesforce.com/docs/atlas.en-us.api_rest.meta/api_rest/resources_composite.htm