Is there any way to change username field label in user authentication login page?

According to documentation LoginView has an attribute called authentication_form (typically just a form class). Defaults to AuthenticationForm.

You can create a form class that inherits from AuthenticationForm, set the label of the username field and assign it to your LoginView over authentication_form attribute.

forms.py

from django import forms    
from django.contrib.auth.forms import AuthenticationForm, UsernameField


class CustomAuthenticationForm(AuthenticationForm):
    username = UsernameField(
        label='Team Name',
        widget=forms.TextInput(attrs={'autofocus': True})
    )

views.py

from django.contrib.auth.views import LoginView

from .forms import CustomAuthenticationForm


class CustomLoginView(LoginView):
    authentication_form = CustomAuthenticationForm

urls.py

urlpatterns = [
    path('login/', CustomLoginView.as_view(), name='login'),
]