Hi!
No, I don't believe there is a way to cut pieces. You just have to work with the pieces there are.
You can, however, clip. (Use pieces "illegally" by putting pieces inside other pieces, or placing them in positions that would be impossible in real life.)
You can use clipping to make "new" pieces, like taking bits of string and putting them together in a shape to make a "piece". There are some pretty elaborate builds made entirely out of string, even tiny LEGO bricks that can fit in a minifigure's hand! My brother, @SlimBrick1, made one of those in response to all the colossal bricks users were making. https://mecabricks.com/en/models/N02g6m7LaLD If you go to the links in this model, you'll see some even TINIER ones!

Just don't expect your models to get on the front page if you clip in them; normally, they only put models that would be buildable in real life there.

Hope I was of some help!
-Tall

That was very helpful. Thank you for your help!
-1cy

Not a problem! I'm glad you figured it out. 👍