You may be able to configure certain aspects of VNC Server or VNC Viewer from an Options or Properties dialog, or from an in-app Settings menu on your tablet or phone. Note that for VNC Server, you must typically be an administrator:
Sometimes, you might need to configure VNC Viewer and VNC Server in conjunction, for example when tweaking performance.
Advanced users can use the parameter system to fine-tune almost any aspect of VNC Connect. This is available either from the Expert tab of the Options dialog, or at the command line.