Without going into too many details, the main difference between CISC assemblies, such as Intel IA-32 and x64, and RISC assembly languages associated with architectures such as ARM, is the complexity of their instructions.
CISC assembly languages have more complex instructions. They focus on completing tasks using as few lines of assembly instructions as possible. To do that, CISC assembly languages include instructions that can perform multiple operations, such as mul in Intel assembly, which performs data access, multiplication, and data store operations.
In the RISC assembly language, assembly instructions are simple and generally perform only one operation each. This may lead to more lines of code to complete a specific task. However, it may also be more efficient, as this omits the execution of any unnecessary operations.