Twitter aims to wean away users who use direct messaging apps like WhatsApp.
Twitter plans to improve its direct messaging service to compete against Facebook acquired WhatsApp.
WhatsApp has more than 500 million users and it is a standalone app, but Twitter does not have a standalone messaging app to compete against WhatsApp.
Twitter's direct messaging service only allows mutual followers to send messages to each other, and two verified account holders to exchange messages even if they do not follow each other.
The company said: "Over the next few weeks, we're rolling out an update that makes deleting DMs more consistent across web and mobile.
"We're also making an update to the Twitter iPhone and Android apps that will allow you to access your entire DM history."
Back in April, Twitter introduced pop-up notifications for messages on its website but no other major changes were made to the website.
Twitter's CEO, Dick Costolo, said: "There's a real opportunity for us, when we think about our private messaging, to strengthen the core of our Twitter product by making it easier for users to move more fluidly between the public conversation that happens everywhere on Twitter, and the private conversation between you and a friend or you and a few friends."