As we transition to the new Hyland Community, some post links may be temporarily disrupted as we finalize redirects. We apologize for the inconvenience and are working to resolve this as quickly as possible. Details.
I can't see complete task function in API?
Which API? ReST, Java, JavaScript (server-side), JavaScript (client-side, e.g. NPM module "alfresco-js-api")?
If you want meaningful help please be a bit more elaborate on your questions.
This Alfresco Content Services REST API Explorer
WorkflowApi
That is the new v1 ReST API. It allows to complete a task by performing an update on it via a PUT request on /tasks/{taskId}. See the details of that operation on how to transition / complete / claim a task.
There is no approve and reject function.