I presume you mean "Macro", yes?

If so, what language - 'C', assembler, or what?

The macro facilities of 'C' are defined by the language - and it is certainly possible to pass parameters to Macros in 'C'.
See any standard 'C' textbook.
Also be careful to pay attention to the risks involved...

The Macro facilities of different assemblers depend on which particular one you're using.
The facilities available will be described in the Assembler's Manual


Do you understand the basic difference between Macros and "functions"?

Functions are CALLed, but Macros simply expand to some in-line code;
Thus, functions exist at run-time, but Macros do not.

Therefore, Macros cannot stricly "return" a result as a function does.

However, you could write your macro such that it leaves its result in some variable, register, or memory location ready for use by subsequent code...