RAM (Random Access Memory) is volatile working memory: your computer loads active programs and data into it so the CPU can access them quickly. When power is cut, RAM contents are lost. More RAM usually helps multitasking and memory-heavy apps.
ROM (Read-Only Memory) is non-volatile memory that keeps its data without power. It typically stores firmware such as BIOS or UEFI—the early instructions that initialize hardware and start the boot process. ROM is mostly read-only (or rarely rewritten via firmware updates), smaller than RAM, and not the place where everyday apps run.
Source: What is ROM? Understanding RAM vs ROM in Computer Memory — HP