All information are automatically saved locally in AppManager, there is no need to press a save button anywhere. Once you are ready to publish your changes to the stores, click on the "Upload" button and AppManager will upload all
General Information to the store.
You can see the progress of the upload via the card at the top of the page. Once the upload is completed the card will disappear. You can review any information from previous uploads by clicking on the bell icon at the top navigation bar to open the notifications window.