Having trouble adjusting to the new Press to Unlock feature? iOS 10 brings many new features and options to use or turn off these features. Most people embrace the new features; however, some people are uncomfortable with changes.
To disable Press to Unlock feature and open the iPhone with Touch ID:
Open the Settings app > General > Accessibility > on the Home Button page, there is a toggle for Rest Finger to Open. Turn this feature on. (Rest Finger to Open default is to be disabled.)
For more ifnormation, Read the iOS Hacker's, How to Turn Off 'Press to Unlock' and Unlock iPhone with Fingerprint Scan Only article.