1. Open the "settings" app.
2. The first section of settings should say the name of the id currently signed in, and below should say "Apple ID, iCloud, iTunes, & App Store." Open this section.
3. Scroll to the very bottom of the page.
4. Click on the button labeled "Sign Out."
5. Select "Sign Out of iCloud and Store."
6. Enter your Apple ID password and click "Turn Off."