what is business card and how it is use?

Business cards typically include a person's name, e-mail address, phone number, website, and company name. They are often used at networking and corporate events to provide other individuals with an easy source for retrieving contact information. They're never inaccessible because of dead spots or Internet outages. You can use them at a remote fishing camp or at an industry conference in the mid-city hotel - or even in situations where cell phones and other digital devices might need to be turned off, such as on planes or in hospitals.

The title of the post does not make it clear that you are promoting an ap. A link and a screenshot would also have helped