Most American television animation is animated in other countries.
Writing, design, storyboarding, color, editing, etc. are all done at US studios.
But the actual finished animation gets produced and compiled overseas.
An informative little thread:
(Before the digital age, art on paper was shipped in boxes across the ocean.)
The studios then make a show based on the storyboard, designs, recordings, and timing.
We provide character designs. Based on the actions in the storyboard, the animation artists make them move fluidly on model.
We design every location but not every background that takes place in a location. The studio fills in the missing scenes.
They employ a lot of talented artists to help make American animated television.
Many US shows are animated in Canada wherein those studios often handle more of the design process than Asian studios would.
This is likely due to a commonality of language and culture.
American studios shipping animation work to other countries more or less became the norm in the 1970s.
Of course there are pros and cons to this system, but it is always adapting with the times, for better or worse.