Surprising question, one of my colleague recently released the Android App called "Easy Text" to solve the exact problem. Using this App you can create and save the Bank Account Details once and you can share the details anytime. "Easy Text" App supporting limitless sharing platform like SMS, E-mail, WhatsApp, Hike, Google Hangout, Facebook, Google Plus, Twitter and many more. App is not only supporting to share Bank Account Details instead you can Save and Share Address, Notes. When I talk to him he told he has the plan to extend the App feature to create own custom template group. So it's a good App to use in my opinion.
Get it from here : https://play.google.com/store/apps/details?id=com.rootaccezlabs.easytext