How can i link HRMS app with my custom inventory app and delete unnecessary erpnext modules and doctypes?

how can i link HRMS app with my custom inventory app and delete unnecessary erpnext modules and doctypes?

Short of forking ERPNext and maintaining your own code, you can’t delete modules or doctypes. If you don’t want them to appear to your users, however, you can create user roles without permission to any of them.