We are new to Episerver and I was not able to find where can I change this notification? How and where can I change the text for the message? Is this customizable out of the box? Any suggestions are grately appreciated.
You can change the notification with help of described examples.
Episerver has ProjectEnhancements on Github. A good source if you need code examples.
I've looked into this not too long ago, and found there's not a ton of flexibility with how the actual email template can be modified. See this post: https://world.episerver.com/forum/developer-forum/-Episerver-75-CMS/Thread-Container/2020/11/approval-sequence-customisations/#230497
Copy/paste from that thread:
"I dug into this a bit, and there's not a super simple way to do it. The actual email template is an embedded resource, and the call to get the template is internal. To get started, you'll need to create a custom formatter (INotificationFormatter) as explained here: https://world.episerver.com/documentation/developer-guides/CMS/using-notifications/usage-examples/. From here, I would suggest digging into this more by decompiling the class "ApprovalHtmlEmailFormatter" in the EPiServer.Cms.Shell.UI.Approvals.Notifications namespace, and looking how the FormatMessagesAsync() is done."