What is the domain and range of f(x)=1x?

The collection of all values for which the function is defined is known as the domain. A function's range is the collection of all possible output values.
As the function $f\left(x\right)=\frac{1}{x}$is defined for all real values of $x$ accept $x=0$. Because at this point function is not defined.
The domain of the function is $R-\left(0\right)$ also the range of the function$f\left(x\right)=\frac{1}{x}$, for every value of $x$ (accept $x=0$) we get $f\left(x\right)=R-\left(0\right)$