Dirty dishes can be put into a dishwasher and the dishwasher will do the work of cleaning the dishes.
But if you have large food particles on the dishes then you should clean and scrape those food particles off the dishes before putting the dishes into the dishwasher.
The larger food particles may cause a clog in the dishwasher drain screen.
Also some dishwasher machines have a hard time of removing really hard to remove large food particles.
So remove the larger food particles and then place the dishes into the dishwasher.
If there's no large food particles or hard to remove grime from the dishes then I place them directly into the dishwasher.
But if there is hard to remove grime or large food particles or even small food particles I remove those first so they do not clog the dishwasher drain screen.