change notification sound for Google Keep Is there a way/user settings which allows assigning a specific RING/Notification sound for Reminders in Google Keep application?

It seems like there is no Settings for this feature provided in the app itself.

My requirement is to have common ring tone for all reminders in Google Keep...No need for separate ring tone for each reminder.

Is this possible?
The UI is not clear in this case, but you can actually change this in the Android Application Notification settings for the Keep app.

(On Android 9): Go to Settings > Apps and Notifications > Keep notes > Notifications. Then you have to tap on each of the Notification Categories individually (e.g. Others, Reminders, Shared notes). As mentioned, from the UI it does not appear these Notification Categories are tappable but they are. You can then set various parameters for that Notification Category such as sound, notification dot, display behavior, ...

More info: How to use notification channels on Android Oreo