How to Make HTTP Requests In React Native IOS application?

you can try like this for send data to server(POST)

let response = await fetch(
    'http://your_url', {
      method: 'POST',
      headers: {
        'Accept': 'application/json',
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({
        username: this.state.name,//data which u want to send
        password: this.state.password,
      })
  });
  let responseText = await response.text();
  if (response.status >= 200 && response.status < 300){
    Alert.alert('Server response', responseText)

  }
  else {
    let error = responseText;
    throw error
    //Alert.alert('Login', error)
  }
} catch(errors) {
  Alert.alert('Login', errors)

  Actions.Documents();
}

Edit: As latest iOS sdk enforces connection to be in https protocol instead of http.you can add an exception to your domain inside info.plist file of the Xcode project.

if you want to allow everything write this inside info.plist

<key>NSAppTransportSecurity</key>
<dict>
<key>NSExceptionDomains</key>
<dict>
    <key>yourdomain.com</key>
    <dict>
        <!--Include to allow subdomains-->
        <key>NSIncludesSubdomains</key>
        <true/>
        <!--Include to allow HTTP requests-->
        <key>NSTemporaryExceptionAllowsInsecureHTTPLoads</key>
        <true/>
        <!--Include to specify minimum TLS version-->
        <key>NSTemporaryExceptionMinimumTLSVersion</key>
        <string>TLSv1.1</string>
    </dict>
 </dict>
</dict>

for more info check this out https://stackoverflow.com/a/31623388/7604342

You can use normal fetch function, only add you http host into exception. In your XCode.