I want to draw curve fitting in other words I want draw fitted values(y_hat) vs dependent variable (x) but i have panel data two groups are "ID and Time(Year)

which are the data positions and time.

I use "np package" and done Nonparametric regression and obtained fitted value.

In my model both Id and Time are random. Then I estimate f(x,Id,Time). These are fitted values.

Now how can I draw curve fitting?