iPad users will be asked to enter their App Store username and password when installing a new app on their iPad. But when you are testing various apps within a short period of time, entering the username and password every time would be quite annoying. Now you can overcome this problem by using the Require Password feature available under the iPad settings.
Tap Settings icon on the Home screen then navigate to General Settings. Under Allowed Content section, tap the Require Password option.
Then select the value for Require Password as 15 minutes. Now when you are try to install an app, the password entered for the first app will be remembered for the next 15 minutes. But if you share your iPad with others, especially the kids at home then it not recommended to enable this option.