Microsoft launched a new app called Send, which lets users write short messages to co-workers without “subject lines and formal email constructs”.

Send is first available for iPhone in the US and Canada, ahead of Android and Microsoft’s own Windows Phone platform. It works for people with Office 365 business and school email accounts, but will soon be “more broadly available”.

Microsoft explained that the app is for users who want to send their co-worker a quick message but either don’t have their phone number or an IM app on their work phone.

The app accesses Outlook’s contacts to find the recipient’s email address and saves the messages in Outlook for later reference.

Features include built-in replies like “on my way,” or “I’ll get back to you”, as well as the ability to see when a reply is being typed out by the recipient.

“With Send, there are no signatures, subject lines or salutations required. Our design principle for the app was to make conversations fast and fluid while keeping the people who are important to you at its core,” Microsoft explained.

Send is the latest app to arrive out of Microsoft Garage, which is where Microsoft’s employees can turn their ideas into actual projects.