Welcome to the forum! There are a lot of great people here willing to lend a hand anytime. Often using the search feature (in the toolbar at the top of every page) will lead you to the answers you're looking for. If not, feel free to post a question in the appropriate area.
Please take a moment to view the information linked below my signature to get the most out of your iPad as well as our forum.
Regarding your question, some Apps are "universal", that is there are versions for the iPhone as well as the iPad. Many developers allow both versions to be purchased at the same time on the App store. When you sync your iPhone or iPad the app will automatically download. If you don't want the app on one of your devices, simply delete it by tapping and holding the icon until it jiggles, then tap on the circled "X" in the upper right-hand corner. Going forward it will no longer sync when you connect to iTunes. If you want it back just go to the Apps area in iTunes and check the box next to the app the next time you sync.
BTW, I moved your post to the iPad Help area where you're likely to get a better response to your question.
Welcome again and enjoy!