diff --git a/lib/presentation/components/field/field.dart b/lib/presentation/components/field/field.dart
index 6a1c77b..a985bf1 100644
--- a/lib/presentation/components/field/field.dart
+++ b/lib/presentation/components/field/field.dart
@@ -1,4 +1,5 @@
 import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
 
 import '../../../common/extension/extension.dart';
 import '../../../common/theme/theme.dart';
diff --git a/lib/presentation/components/field/text_form_field.dart b/lib/presentation/components/field/text_form_field.dart
index ce5cab3..bdfd86b 100644
--- a/lib/presentation/components/field/text_form_field.dart
+++ b/lib/presentation/components/field/text_form_field.dart
@@ -4,6 +4,7 @@ class AppTextFormField extends StatelessWidget {
   const AppTextFormField({
     super.key,
     this.hintText,
+    this.helperText,
     required this.title,
     this.controller,
     this.focusNode,
@@ -14,9 +15,11 @@ class AppTextFormField extends StatelessWidget {
     this.validator,
     this.readOnly = false,
     this.onTap,
+    this.inputFormatters,
   });
 
   final String? hintText;
+  final String? helperText;
   final String title;
   final TextEditingController? controller;
   final FocusNode? focusNode;
@@ -27,6 +30,7 @@ class AppTextFormField extends StatelessWidget {
   final String? Function(String?)? validator;
   final bool readOnly;
   final Function()? onTap;
+  final List<TextInputFormatter>? inputFormatters;
 
   @override
   Widget build(BuildContext context) {
@@ -39,6 +43,7 @@ class AppTextFormField extends StatelessWidget {
           controller: controller,
           focusNode: focusNode,
           keyboardType: keyboardType,
+          inputFormatters: inputFormatters,
           onChanged: onChanged,
           cursorColor: AppColor.primary,
           style: AppStyle.md.copyWith(
@@ -50,6 +55,8 @@ class AppTextFormField extends StatelessWidget {
           readOnly: readOnly,
           decoration: InputDecoration(
             hintText: hintText,
+            helperText: helperText,
+            helperStyle: AppStyle.sm.copyWith(color: AppColor.textSecondary),
             prefixIcon: prefixIcon,
             suffixIcon: suffixIcon,
             prefixIconConstraints: const BoxConstraints(
diff --git a/lib/presentation/pages/auth/login/widgets/phone_field.dart b/lib/presentation/pages/auth/login/widgets/phone_field.dart
index 7caa40b..4baceda 100644
--- a/lib/presentation/pages/auth/login/widgets/phone_field.dart
+++ b/lib/presentation/pages/auth/login/widgets/phone_field.dart
@@ -1,4 +1,5 @@
 import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 
 import '../../../../../application/auth/check_phone_form/check_phone_form_bloc.dart';
@@ -36,6 +37,9 @@ class _LoginPhoneFieldState extends State<LoginPhoneField> {
 
   void _clearText() {
     _controller.clear();
+    context.read<CheckPhoneFormBloc>().add(
+      const CheckPhoneFormEvent.phoneNumberChanged(''),
+    );
     setState(() {});
   }
 
@@ -44,13 +48,19 @@ class _LoginPhoneFieldState extends State<LoginPhoneField> {
     return AppTextFormField(
       title: 'Masukkan no telepon',
       hintText: '8712671212',
+      helperText: 'Harus diawali angka 8',
       controller: _controller,
       focusNode: _focusNode,
       keyboardType: TextInputType.phone,
+      inputFormatters: [_PhoneAfterCountryCodeFormatter()],
       validator: (value) {
-        if (context.read<CheckPhoneFormBloc>().state.phoneNumber.isEmpty) {
+        final phoneNumber = context.read<CheckPhoneFormBloc>().state.phoneNumber;
+        if (phoneNumber.isEmpty) {
           return 'Masukkan no telepon';
         }
+        if (!phoneNumber.startsWith('8')) {
+          return 'No telepon harus diawali angka 8';
+        }
 
         return null;
       },
@@ -80,3 +90,27 @@ class _LoginPhoneFieldState extends State<LoginPhoneField> {
     );
   }
 }
+
+/// Prefix +62 sudah tampil di field, jadi input harus langsung diawali 8.
+/// Ketikan `0`/`6` di awal ditolak; tempelan `08…`, `62…`, atau `+62…`
+/// dirapikan jadi `8…`.
+class _PhoneAfterCountryCodeFormatter extends TextInputFormatter {
+  @override
+  TextEditingValue formatEditUpdate(
+    TextEditingValue oldValue,
+    TextEditingValue newValue,
+  ) {
+    var digits = newValue.text.replaceAll(RegExp(r'\D'), '');
+    if (digits.startsWith('62')) digits = digits.substring(2);
+    digits = digits.replaceFirst(RegExp(r'^0+'), '');
+
+    if (digits.isEmpty) return const TextEditingValue();
+    if (!digits.startsWith('8')) return oldValue;
+    if (digits == newValue.text) return newValue;
+
+    return TextEditingValue(
+      text: digits,
+      selection: TextSelection.collapsed(offset: digits.length),
+    );
+  }
+}
diff --git a/pubspec.yaml b/pubspec.yaml
index 01052ad..e4b39a3 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -3,7 +3,7 @@ description: "A new Flutter project."
 
 publish_to: "none"
 
-version: 1.0.0+1
+version: 1.0.0+2
 
 environment:
   sdk: ^3.8.1