Journeys - Task Type: External URL
With reference to FAQs on Doc ID 2662513.1, if a specific task is not available as an Application Task within Checklists, then you can create the task as an External URL task type and provide the deep link of that page (provided there is one) in the URL field. You can check for deep links available in your environment by navigating to Tools > Deep Links.
I have setup a Task within a Checklist, selecting Task Type 'External URL', and then adding the relevant Deep Link.
Upon adding the Journey from Me - Employee, when viewing the Task, the Deep Link is displayed as 'Go to website'.