currently download an app with itunes...
how to install it to ipad without delete current app within ipad .

any body know..need help.

Is it the same app? By default, you can't install the same app twice on the same iOS device. But if you want to install apps using iTunes, go to device > Apps > select apps you want to install > click Install or you can drag the app to the iPad home screen.

This post has been edited by Townshend: Mar 4 2015, 08:17 PM

i m downloaded new app from itunes that my ipad no install before...
how to install it into ipad?

Make sure you use the same Apple ID for the download > connect your iPad to iTunes > click on your device > go to Apps tab in iTunes > select apps you want to instal > click Install and then Apply.

is it itunes only can use 1 user id?
every time i sign out and login direffent id itunes cannot authorize pc.

what will happen if my ipad use 2 user id which direffent store to download .

You can use more than one Apple ID on iTunes, but of course, you have to sign out from one ID and then sign in to another.

Please refer https://support.apple.com/en-my/HT203160

You can still use apps that you download with different Apple ID, but when you want to update the apps, you’ll have to sign in to the same Apple ID that you used to download them.