"You can do everything by yourself."
Translation:אתה יכול לעשות הכל בעצמך.
You can use either הכול or את הכול. I feel like there's a slight difference in meaning between them, but I can't put my finger on it.
I think it's that הכל is more general, and את הכל is for if you're referring back to something specific, say if you have a list of things to do.
I'm not a native speaker, but the explanation airelibre gave is exactly how I perceive these sentences.
I am bit puzzled too. I thought it should be either לעשות כל or לעשות את הכל, but not לעשות הכול. ???