Yes! 10,000+ daily steps tracked with Jawbone UP, Fitbit, or Moves can count as a pact activity. You can also use the Step Tracker built right into the app!
Please keep in mind that the step tracking in the app is only available on iPhone 5S, 6, 6+, iPad Air and iPad Mini. Other iOS devices are not equip with Motion Activity functionality.
To give Pact permission to access your iOS device's Motion Activity information you must visit your Privacy settings for Motion Activity and scroll to Pact to make sure that Pact can access your steps information. You can turn this functionality on by selecting Settings > Privacy > Motion Activity and scroll down to Pact to ensure the toggle is set to on.