The ARM processor does not have bit variables. It does not have any processor instructions working on a single bit, so there is no meaning to have a hard-coded specific bit variable data type.

There are ARM architectures that include single-bit manipulation, like the Cortex-M... series.

The only thing special is that some ARM chips have a special memory-mapping feature where some integer variables also have an alias address where each individual bit in the integer can also be accessed at a different integer at the aliased address. This allows the source code to write to a virtual integer variable that will result in a single-bit access in the actual container integer. Look closer at this feature in Cortex-class ARM chips. Also, some Cortex-based chips have some integer variables and port registers that can be written to where the least significant bits of the access address will work as a mask to specify which bits of the port register that should be accessed.