In C how much space does a bool (boolean) take up? Is it 1 bit, 1 byte or something else?

If you are referring to C99 _Bool try:

printf("%zu\n", sizeof(_Bool)); /* Typically 1. */

Note the standard says:

6.2.5

An object declared as type _Bool is large enough to store the values 0
and 1.

The size cannot be smaller than one byte. But it would be legal to be larger than one byte.