Your daily steps should come automatically from the Google Fit app on your phone (assuming you're using an Android device).
If they don't, just follow these steps:
Open our app
Go to Account, then Settings
Check Connected Apps. Make sure that the Google Fit toggle is enabled.
Once this is done, your step activity should start being sent to the app automatically.
Using a fitness tracker?
If you're using a wearable tracker that does not sync with Google Fit such as a Fitbit or Galaxy Watch, read this article to see how you can still connect it to the app.