x86 assembly works on Intel and AMD CPUs that use the x86 architecture, including:

• 32-bit (x86) CPUs

• 64-bit (x86-64 or x64) CPUs (also support x86 instructions)

Most modern Intel and AMD desktop/laptop CPUs support x86/x64.
Not used on ARM-based CPUs (like most smartphones or Apple M1/M2 chips).