You can use the Edit window to change a command's settings.
If you're in Command or DMIS mode, press the Tab key to go to the editable field you want to change. Either type in a new value or press F7 or F8 to cycle forward or backward through a list of available values. You can also move your pointer over a toggle field and after a moment it changes to a gray background. You can then click on that to select from a menu of available values.
If you edit a feature or dimension's ID using the Edit window, PC-DMIS asks if you want to make this ID the default for that same feature or dimension type. If you click Yes, features or dimensions of that same type, when created later, will use the new ID as the default. If you click No, then future IDs continue to use the current default value.