[Solved]-React Navigation Header change with screen-Reactjs

Every StackNavigator brings one header, first one is from RootNavigator = StackNavigator({ and bottom one that you see is coming from Clientes: { screen: StackNavigator({.

First of all, seams header: null in your Clientes: { screen: StackNavigator({ doesn't have any effect. You should try headerMode: 'none' instead, this will remove the blank header from Index but also header from Teste with the title and back button, which is doesn't solve all your problems.

So I would suggest different navigators structure:

RootNavigator(StackNavigator)
- Welcome
- Index
- Teste
- User(TabNavigator)
    - Clientes 
    - Opcoes

What you should you do next is set different header (default one, with back button) for Teste inside component itself, something like this:

import { Header } from 'react-navigation';

Teste.navigationOptions = ({ navigation, screenProps }) => ({
    return {
        header: <Header {...screenProps} {...navigation} />
    }
});

You can even make your own header Component and use it in Teste.navigationOptions.