diff --git a/src/core/note_app.dart b/src/core/note_app.dart
index 39a3f92..a4ca719 100644
--- a/src/core/note_app.dart
+++ b/src/core/note_app.dart
@@ -1,6 +1,191 @@
+import 'dart:io';
+import '../models/note_model.dart';
+
+/// Manages the operations of the note-taking program (create, edit, delete, search, display).
 class NoteApp {
-  // TODO: Complete the run function
-  void run() {
-    print('Hello, world!');
+  List<Note> notes = [];
+
+  static const int boxWidth = 50;
+  final String horizontalLine = '═' * (boxWidth - 2);
+  final String header = "╔${'═' * (boxWidth - 2)}╗";
+  final String footer = "╚${'═' * (boxWidth - 2)}╝";
+
+  /// Creates a new note and adds it to the list of notes.
+  void createNote() {
+    _printHeader("Create a New Note");
+
+    final title = _getInput("Enter the note title: ");
+    if (title.isEmpty) {
+      print("Note title cannot be empty. Please provide a title.\n");
+      return;
+    }
+
+    if (_noteExists(title)) {
+      print(
+          "A note with the title '$title' already exists. Please choose a different title.\n");
+      return;
+    }
+
+    final content = _getInput("Enter the note content: ");
+    final newNote = Note(
+      title: title,
+      content: content.isEmpty ? "None" : content,
+    );
+
+    notes.add(newNote);
+    print("The note is successfully created!\n");
+  }
+
+  /// Displays all notes in the list.
+  void displayNotes() {
+    _printHeader("All Notes");
+
+    if (notes.isEmpty) {
+      print("No notes to display.");
+    } else {
+      for (var note in notes) {
+        _printNoteContent(note.title, note.content);
+      }
+    }
+  }
+
+  /// Edits the title and content of a note.
+  void editNote() {
+    _printHeader("Edit Note");
+
+    if (notes.isEmpty) {
+      print("No notes to edit.");
+      return;
+    }
+
+    final title = _getInput("Enter the title of the note to edit: ");
+    final note = _findNoteByTitle(title);
+    if (note == null) {
+      print("Note with title '$title' not found.\n");
+      return;
+    }
+
+    final newTitle = _getInput("Enter a new title: ");
+    final newContent = _getInput("Enter new content: ");
+    note.title = newTitle.isEmpty ? note.title : newTitle;
+    note.content = newContent.isEmpty ? note.content : newContent;
+
+    print("The note is successfully edited!");
+  }
+
+  /// Deletes a specific note from the list.
+  void deleteNote() {
+    _printHeader("Delete Note");
+
+    if (notes.isEmpty) {
+      print("No notes to delete.");
+      return;
+    }
+
+    final title = _getInput("Enter the title of the note to delete: ");
+    final note = _findNoteByTitle(title);
+
+    if (note == null) {
+      print("Note with title '$title' not found.");
+      return;
+    }
+
+    notes.remove(note);
+    print("Note deleted: ${note.title}");
+  }
+
+  /// Searches for a specific note by title or content.
+  void searchNotes() {
+    _printHeader("Search Notes");
+
+    if (notes.isEmpty) {
+      print("No notes to search.");
+      return;
+    }
+
+    final query = _getInput("Enter the title or content of the note to search: ");
+    final matchingNotes = notes.where((note) =>
+        note.title.contains(query) || note.content.contains(query)).toList();
+
+    if (matchingNotes.isEmpty) {
+      print("No matching notes found.");
+    } else {
+      print("Matching notes:");
+      for (var note in matchingNotes) {
+        _printNoteContent(note.title, note.content);
+      }
+    }
+  }
+
+  /// Helper method to get input from the user.
+  String _getInput(String prompt) {
+    stdout.write(prompt);
+    return stdin.readLineSync()?.trim() ?? "";
+  }
+
+  /// Helper method to check if a note with the given title already exists.
+  bool _noteExists(String title) {
+    return notes.any((note) => note.title == title);
+  }
+
+  /// Helper method to find a note by its title.
+  Note? _findNoteByTitle(String title) {
+    try {
+      return notes.firstWhere((note) => note.title == title);
+    } catch (e) {
+      return null;
+    }
+  }
+
+  /// Helper method to print header with a title.
+  void _printHeader(String title) {
+    print(header);
+    print("║ ${_centerText(title, boxWidth - 4)} ║");
+    print(footer);
+  }
+
+  /// Helper method to print note content within a box.
+  void _printNoteContent(String title, String content) {
+    print("╔${'═' * (boxWidth - 2)}╗");
+    print("║ ${_centerText(title, boxWidth - 4)} ║");
+    print("╠${'═' * (boxWidth - 2)}╣");
+    print("║ Content:".padRight(boxWidth - 1) + "║");
+    _printWrappedContent(content);
+    print("╚${'═' * (boxWidth - 2)}╝");
+  }
+
+  /// Helper method to wrap and print content within the box width.
+  void _printWrappedContent(String content) {
+    final int contentWidth = boxWidth - 4;
+    final lines = _wrapText(content, contentWidth);
+    for (var line in lines) {
+      print("║ ${line.padRight(contentWidth)} ║");
+    }
+  }
+
+  /// Helper method to wrap text within a specific width.
+  List<String> _wrapText(String text, int width) {
+    final List<String> lines = [];
+    while (text.isNotEmpty) {
+      if (text.length <= width) {
+        lines.add(text);
+        break;
+      } else {
+        int spaceIndex = text.lastIndexOf(' ', width);
+        if (spaceIndex == -1) {
+          spaceIndex = width;
+        }
+        lines.add(text.substring(0, spaceIndex));
+        text = text.substring(spaceIndex).trimLeft();
+      }
+    }
+    return lines;
+  }
+
+  /// Helper method to center text within a given width.
+  String _centerText(String text, int width) {
+    final int padding = (width - text.length) ~/ 2;
+    final String paddingStr = ' ' * padding;
+    return paddingStr + text + paddingStr.padRight(width - text.length - padding);
   }
 }
diff --git a/src/main.dart b/src/main.dart
index 88398d1..11bddba 100644
--- a/src/main.dart
+++ b/src/main.dart
@@ -1,5 +1,52 @@
+import 'dart:io';
 import 'core/note_app.dart';
 
-void main(List<String> args) {
-  NoteApp().run();
+/// Entry point for the note-taking application.
+void main() {
+  final noteApp = NoteApp();
+
+  while (true) {
+    try {
+      print("╔═════════════════════════════════════════════════════════╗");
+      print("║                   Welcome to NoteApp                    ║");
+      print("╠═════════════════════════════════════════════════════════╣");
+      print("║                    1. Create a note                     ║");
+      print("║                    2. Edit a note                       ║");
+      print("║                    3. Delete a note                     ║");
+      print("║                    4. Search for a note                 ║");
+      print("║                    5. Display all notes                 ║");
+      print("║                    6. Exit                              ║");
+      print("╚═════════════════════════════════════════════════════════╝\n");
+      stdout.write("Enter your choice: ");
+
+      final choice = int.tryParse(stdin.readLineSync() ?? "") ?? -1;
+
+      switch (choice) {
+        case 1:
+          noteApp.createNote();
+          break;
+        case 2:
+          noteApp.editNote();
+          break;
+        case 3:
+          noteApp.deleteNote();
+          break;
+        case 4:
+          noteApp.searchNotes();
+          break;
+        case 5:
+          noteApp.displayNotes();
+          break;
+        case 6:
+          print("\nExiting the program.");
+          exit(0);
+        default:
+          print("Invalid choice. Please choose a number between 1 and 6.");
+      }
+    } on FormatException {
+      print("Invalid input. Please enter a valid number.");
+    } catch (e) {
+      print("An unexpected error occurred: $e");
+    }
+  }
 }
diff --git a/src/models/note_model.dart b/src/models/note_model.dart
index 788b69e..663b64b 100644
--- a/src/models/note_model.dart
+++ b/src/models/note_model.dart
@@ -1,2 +1,9 @@
-//TODO: Define a note model class
-class NoteModel {}
+class Note {
+  late String title;
+  late String content;
+
+  Note({
+    required this.title,
+    required this.content,
+  });
+}