Yes you can!
If you’re using World Walking on an iPhone 5s or above* you can take advantage of your phone’s built-in pedometer and Health Kit. This will automatically bank any new steps you’ve taken since you last used the app. For example, if you enable this feature on Monday evening and open the app at lunch on Tuesday, you’ll automatically bank your walk to work. As long as take your iPhone with you when you’re walking, all of your steps will be banked.
To enable this feature, go to the app’s Settings screen, tap on Apps then Health Kit. You may be asked to grant World Walking permission to access your Health Kit data and to access your motion data when you next re-open the app. We only need permission to read your phone’s step count and you can revoke this at any time via your iPhone’s Settings app.
* Compatible devices include iPhone 5s and newer.