Friendships Create Request

Allows the authenticating users to follow the user specified in the ID parameter.

Returns the befriended user in the requested format when successful. May throw exceptions in case of failure.

use Widop\Twitter\Rest\Friendships\FriendshipsCreateRequest;

$request = new FriendshipsCreateRequest();

$request->setUserId('123546789');
$userId = $request->getUserId();

$request->setScreenName('noradio');
$screenName = $request->getScreenName();

$request->setFollow(true);
$follow = $request->getFollow();

$users = $twitter->send($request);

You can get more informations here.