Each platform app comes with a Help & Support link in the Accounts section of their app.
When your platform account is created, you can provide a support email address or a support URL.
If you provide a support contact name & email address, then the user will have access to these details when selecting Help & Support.
If you provide a support URL, the user will be directed to that page when selecting Help & Support, e.g. this could go to a contact form.
To access the platform's public user help knowledge base, go here.
If users are having trouble downloading or installing a platform app from the Google Play Store, please follow the troubleshooting provided by Google.