Facebook offers it's messenger app to communicate with your friends. You can add your friends on it directly by their username or with the use of contact number. You can also send a story, docs file, images,etc. But, you have to confirm the request of your friends to keep them in touch and for communication. If you see that the Facebook Messenger app keeps crashing, then make sure you are working on an updated version and also ensure the internet connection is strong enough. If you still face the same, then contact Facebook if you have a problem and resolve it as soon as possible. https://www.customercare-email.net/facebook-customer-service/