How can I change "someone" to something else?

Go to notification list > edit notification > Design tab > Click on Text-editor

Someone is fall back values for dynamic "name" keywords like {{F_name}}, {{L_name}},{{UserName}}

When we are not receiving name values from your data source or integration setting, we are showing "someone"  value in the place of name.

You can change this text & write a custom names like someone, marketers, students, or anything you would like to show.