1) Open Apple Health app and select the desired metric
2) Tap on "Share Data" button
3) Make sure that Today is included in both "Share data with" and "Data sources" list and that all respective switches are turned to on.
4) If Today does not appear at all under the data sources list, please open today, remove the health card and add it again. It should automatically prompt you to allow access to HealthKit. Press "All categories on" and then "Allow" and the card should appear properly.