You can email students from the Gradebook interface in Canvas, but you cannot send messages on an individual basis and instead must choose from categories of students. You can send messages to your students based on the following assignment categories: Haven't submitted yet, Haven't been graded, Scored less than X number of points, Scored more than X number of points. Even though one message (the same message) will be sent to multiple students at the same time, each student will receive an individual message, so there is no need to worry about students seeing how their classmates are performing in the course via these messages.

Further resources:

• How do I send a message to my students from the New Gradebook?