Per default setting all services log only to journal and not to console. You can check the settings of a service with:
sudo systemctl show MyService.service | grep -Fi Standard
And you should get something like.
StandardInput=null StandardInputData= StandardOutput=journal StandardError=inherit
If you want to change it, you have to set StandardOutput to journal+console.
The full options are documented in the man pages. You can look into man page of systemd.directives:
man systemd.directives
Search for StandardOutput and you will find a reference to the man page of systemd.exec. There you will find every option of this directive.
To change it you should call:
sudo systemctl edit MyService.service
and then add or change the line of StandardOutput to
[Service] StandardOutput=journal+console
After all you should reload systemd configuration:
sudo systemctl daemon-reload