Python Manage.Py
One project may have many application in it & you can create app using below code.
django-admin startapp my_new_app.
Also you can reuse same app in multiple projects.
For Hrm you should create new app instead of new project.
Example : One ERP projects may have many apps like hrm, sales, purchase, inventory etc.. & we can reuse same apps into another ERP projects also if needed.
Hope above clarifications works for you.
I am very New to Python web development ,so got confuse while learning ,when we create new Project with the command --django-admin startProject 'ProjectName' 
It Created a project folder in my drive  and then we  create application in it  suppose with the name of "calculator", we start working in it ,
but after some more  requirement we have to  create a new different Project with the Name of the Hrms so the question arise for this again we have to run the same command django-admin startProject 'ProjectName' and then we have to create application in it or we  can create in it?