Due to the difficulties humans have reading and writing machine code in binary, we created Assmebly Language.
Assembly Language uses mnemonics - commonly 3 letter abbreviations of English words. Each mnemonic is directly linked to one machine code instruction.
When a program is written in Assembly Langauge, the mnemonics are converted to their binary machine code equivalents to be ran on the CPU. This translation is done by an Assembler.
Advantages of Assembly Languages
Disadvantages of Assembly Language