Can an emploeye attach document to a Journey anytime?

Hi

We have a requirement where a journey will be assigned to an employee in certain scenarios. Employee will review/complete different tasks of the Journey. of the task is where can access and upload a document to the journey anytime. For example, a journey was assigned to an employee today, employee starts accessing the Journey task from today and complete all the task which were due. Now after 1-month, same employee should be able to access the same journey and should be able to attach the document. After 2 months, employee may need to attach another document to the same Journey.