# ./components/SignUp.js

...

  <Text style={styles.authInputLabel}>Email</Text>
  <TextInput
    style={styles.authTextInput}
    autoCapitalize={'none'}
    keyboardType={'email-address'}
    placeholder={"example@email.com"}
    placeholderTextColor={'#fff'}
    #Set the state userEmail value to newly entered text
    onChangeText={(text) => this.setState({userEmail: text})}
  />
  <Text style={styles.authInputLabel}>Password</Text>
  <TextInput
    secureTextEntry={true}
    style={styles.authTextInput}
    placeholder={"password"}
    placeholderTextColor={'#fff'}
    #Set the state userPassword value to newly entered text
    onChangeText={(text) => this.setState({userPassword: text})}
  />

...