You can install gdm-settings with
sudo apt install gdm-settings libglib2.0-dev-bin
If you also like to set a custom background for the lockscreen, you can use an extension
Install the extension-manager with
sudo apt install gnome-shell-extension-manager
then you can install and manage the extensions with it.
That may be one
or that
Here are some guides how to install the extensions if you are interested: