How to make a line wrap if?

Question

css

there is a code

<form class="formmsg" method="POST" action="../im/msg.php">
                        <input type="text" name="msg" class="inmsg" placeholder="введите сообщение... " autofocus="1" autocomplete="off">
                        <button class="send_message" name="sendmsg"><img src="https://img.icons8.com/android/24/000000/paper-plane.png"/></button> 
                    </form>

it is necessary to make the line go when it comes to the end, and do not go beyond the aisle