diff --git a/README.md b/README.md
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--- a/README.md
+++ b/README.md
@@ -2,6 +2,8 @@
 
 ##### NOTE: Still not working as intended.
 
+Documentations can be found [here](https://binhonglee.github.io/LibrarySystem/).
+
 ---
 
 ## Dependencies
diff --git a/docs/index.md b/docs/index.md
index 7dfe86b..dfeb172 100644
--- a/docs/index.md
+++ b/docs/index.md
@@ -1,7 +1,21 @@
 # Documentations
 
+- [Main](#main)
 - [Book](#book)
 - [Book Factory](#book-factory)
+- [User](#user)
+- [User Factory](#user-factoru)
+
+# Main
+
+## Functions
+
+| Return | Method | Description |
+|:-------|:-------|:------------|
+| boolean | borrowBook(User user, Book book) | Return if the borrow of the book on both `BookFactory` and `UserFactory` is successful
+| boolean | returnBook(User user, Book book) | Return if the return of the book on both `BookFactory` and `UserFactory` is successful
+| int[] | calDueDate(int days) | Calculate the due date from the current date according to user's permission
+| int[] | currentDay() | Returns the current date in an array form |
 
 # Book
 
@@ -40,3 +54,38 @@
 | Book | getBook(int index) | Returns the book of the given index if it exist, else throw null pointer exception |
 | Book | getBook(String title) | Returns the book of the given title if it exist, else throw null pointer exception |
 | void | update(Book newbook) | Replaces the existing book of the same id with this new one |
+
+# User
+
+## Constructors
+
+| Method | Description |
+|:-------|:------------|
+| User(String name, int id, int limit) | Create a new User with given name, id and limit |
+
+## Functions
+| Return | Method | Description |
+|:-------|:-------|:------------|
+| String | getName() | Returns the name of the user |
+| int | getId() | Returns id of the user |
+| void | setName() | Set the name of the user |
+| boolean | status() | Check if the user reached the limit of amount of books the user can borrow |
+| List<Integer> | bookStatus() | Return a list consisting of book ids for all the books rented by the user |
+| boolean | borrowNewBook(int id) | Check if the user status if true then add the id to the list of the books borrowed by the user |
+| boolean | returnBook(int id) | Check if the book is borrowed by the user then remove it from the list |
+
+# User Factory
+
+## Constructors
+
+| Method | Description |
+|:-------|:------------|
+| UserFactory() | Creates a new empty factory |
+
+## Functions
+| Return | Method | Description |
+|:-------|:-------|:------------|
+| User | newUser(String name, int limit) | Creates a new user and returns the created user |
+| User | getUser(String name) | Gets the user with the given name from the factory |
+| User | getUser(int index) | Gets the user with the given id from the factory |
+| void | update(User oldUser, User newUser) | Update by replacing the existing user with the new one |