How can i customize the Module in Library Management System

can anyone help me for this question

What do you want to customize?
Have you created the app from scratch?

yes, i have created app, but when i am creating the doctype that time not showing the module library management

May be into library_management/config/
you shoud put something like
# Library Management
“module_name”: “Library Management”,
"category": “Modules”,
“label”: _(“Library Management”),
“color”: “#589494”,
“reverse”: 1,
“icon”: “octicon octicon-book”,
“type”: “module”,
“description”: “Library management, sample tutorial module”

I’ve rewrite the library module with updated feature and new stuff from v12

Thank You, i got the solution

Then it is good usage to mark this post as solved and explain your solution. It can help other later on.

I logged in from administrator and create the Library Management module by using module def…

Also active the developer mode for customization…