The disappearance of the messages was first seen in Snapchat. Now, you can enable the feature in your WhatsApp Beta version, in individual or group chats.

After enabling the feature, your chats will be deleted after seven days. 

By the end of this month, this feature will be available in iOS, Android, and Linux-based KaiOS devices, including WhatsApp web.

Though the feature differs from Telegram and Snapchat, it works as same. 

In Telegram, you can decide the period of your texts before they disappear. On the other hand, in Snapchat, the chats get deleted within 24 hours after it is opened. And, unopened chats disappear after 30 days.

The company shared their statement, "We're starting with 7 days because we think it offers peace of mind that conversations aren't permanent while remaining practical so you don't forget what you were chatting about. The shopping list or store address you received a few days ago will be there while you need it, and then disappear after you don't".

There is an enable, and a disable option, it will depend on the individual, but in groups, the admins will have the control. 

There will be options to retain your texts. If the person is enabling the feature, then he or she can take a screenshot or copy the messages within seven days. The disappeared messages will be stored in the backup but once restored; it won't reappear.

Now, Facebook Messenger also has a vanish mode.