HbA1c data can be found under the Home section of the app. Click Home at the bottom menu, and you will see a blue icon with HbA1c at the top of the screen. (If you don't see this section, press gently on the Blood Glucose field in orange without opening it, hold and slide left.)
To add new data, click on + in the blue field. Then add the amount of HbA1c in percent (%). Afterward, you will need to select the date when it was taken. Then click Continue, and your data is saved.
Click on the blue icon with HbA1c at the top of the Home screen to view your history of HbA1c data entries. Here you can also add a new entry.