how to reset the password if user forgot the password in firebase and flutter

Check this. you will get password reset email to the email address that is sent to firebase

firebase_exceptions.dart

import 'package:firebase_auth/firebase_auth.dart';

enum AuthStatus {
  successful,
  wrongPassword,
  emailAlreadyExists,
  invalidEmail,
  weakPassword,
  unknown,
}

class AuthExceptionHandler {
  static handleAuthException(FirebaseAuthException e) {
    AuthStatus status;
    switch (e.code) {
      case "invalid-email":
        status = AuthStatus.invalidEmail;
        break;
      case "wrong-password":
        status = AuthStatus.wrongPassword;
        break;
      case "weak-password":
        status = AuthStatus.weakPassword;
        break;
      case "email-already-in-use":
        status = AuthStatus.emailAlreadyExists;
        break;
      default:
        status = AuthStatus.unknown;
    }
    return status;
  }

  static String generateErrorMessage(error) {
    String errorMessage;
    switch (error) {
      case AuthStatus.invalidEmail:
        errorMessage = "Your email address appears to be malformed.";
        break;
      case AuthStatus.weakPassword:
        errorMessage = "Your password should be at least 6 characters.";
        break;
      case AuthStatus.wrongPassword:
        errorMessage = "Your email or password is wrong.";
        break;
      case AuthStatus.emailAlreadyExists:
        errorMessage =
            "The email address is already in use by another account.";
        break;
      default:
        errorMessage = "An error occured. Please try again later.";
    }
    return errorMessage;
  }
}

reset_password.dart

import 'package:firebase_auth/firebase_auth.dart';
import 'package:school/screens/firebase_exception.dart';

class ResetPasswordScreen extends StatefulWidget {
  static const String id = 'reset_password';
  const ResetPasswordScreen({Key? key}) : super(key: key);

  @override
  State<ResetPasswordScreen> createState() => _ResetPasswordScreenState();
}

class _ResetPasswordScreenState extends State<ResetPasswordScreen> {
  final _key = GlobalKey<FormState>();
  final _emailController = TextEditingController();
  static final auth = FirebaseAuth.instance;
  static late AuthStatus _status;

  @override
  void dispose() {
    _emailController.dispose();
    super.dispose();
  }

  Future<AuthStatus> resetPassword({required String email}) async {
    await auth
        .sendPasswordResetEmail(email: email)
        .then((value) => _status = AuthStatus.successful)
        .catchError(
            (e) => _status = AuthExceptionHandler.handleAuthException(e));

    return _status;
  }

  @override
  Widget build(BuildContext context) {
    var size = MediaQuery.of(context).size;
    return Scaffold(
      body: Container(
        width: size.width,
        height: size.height,
        color: Colors.white,
        child: Padding(
          padding: const EdgeInsets.only(
              left: 16.0, right: 16.0, top: 50.0, bottom: 25.0),
          child: Form(
            key: _key,
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                GestureDetector(
                  onTap: () => Navigator.pop(context),
                  child: const Icon(Icons.close),
                ),
                const SizedBox(height: 70),
                const Text(
                  "Forgot Password",
                  style: TextStyle(
                    fontSize: 35,
                    fontWeight: FontWeight.bold,
                    color: Colors.black,
                  ),
                ),
                const SizedBox(height: 10),
                const Text(
                  'Please enter your email address to recover your password.',
                  style: TextStyle(
                    fontSize: 15,
                    color: Colors.black,
                  ),
                ),
                const SizedBox(height: 40),
                const Text(
                  'Email address',
                  style: TextStyle(
                    fontSize: 15,
                    color: Colors.black,
                    fontWeight: FontWeight.bold,
                  ),
                ),
                const SizedBox(height: 10),
                Container(
                  child: TextFormField(
                    obscureText: false,
                    controller: _emailController,
                    validator: (value) {
                      if (value == null || value.isEmpty) {
                        return 'Empty email';
                      }
                      return null;
                    },
                    autofocus: false,
                    style: const TextStyle(
                        fontSize: 15,
                        fontWeight: FontWeight.bold,
                        color: kDarkGrey),
                    decoration: const InputDecoration(
                      contentPadding:
                          EdgeInsets.symmetric(vertical: 20, horizontal: 20),
                      border: OutlineInputBorder(
                          borderRadius:
                              BorderRadius.all(Radius.circular(30.0))),
                      enabledBorder: OutlineInputBorder(
                        borderSide: BorderSide(
                          color: kBlackText,
                          width: 1,
                        ),
                        borderRadius: BorderRadius.all(
                          Radius.circular(
                            30.0,
                          ),
                        ),
                      ),
                      focusedBorder: OutlineInputBorder(
                        borderSide:
                            BorderSide(color: kSecondaryColor, width: 2.0),
                        borderRadius: BorderRadius.all(
                          Radius.circular(
                            30.0,
                          ),
                        ),
                      ),

                      isDense: true,
                      // fillColor: kPrimaryColor,
                      filled: true,
                      errorStyle: TextStyle(fontSize: 15),
                      hintText: 'email address',
                      hintStyle: TextStyle(
                          fontSize: 17,
                          fontWeight: FontWeight.bold,
                          color: kLightWhiteGray),
                    ),
                  ),
                ),
                const SizedBox(height: 16),
                const Expanded(child: SizedBox()),
                SizedBox(
                  height: MediaQuery.of(context).size.height / 20,
                  child: Material(
                    elevation: 2,
                    borderRadius: BorderRadius.circular(20),
                    color: kSecondaryColor,
                    child: MaterialButton(
                      onPressed: () async {
                        if (_key.currentState!.validate()) {
                          final _status = await resetPassword(
                              email: _emailController.text.trim());
                          if (_status == AuthStatus.successful) {
                            //your logic
                          } else {
                            //your logic or show snackBar with error message

                          }
                        }
                      },
                      minWidth: double.infinity,
                      child: const Text(
                        'RECOVER PASSWORD',
                        style: TextStyle(
                            color: kBlackText,
                            fontWeight: FontWeight.bold,
                            fontSize: 16,
                            fontFamily: 'Poppins'),
                      ),
                    ),
                  ),
                ),
                const SizedBox(height: 20),
              ],
            ),
          ),
        ),
      ),
    );
  }
}