What is it?
In computers, a process is an instance of a program being executed in the main memory. The program itself is static and is just being kept in disk, while its process is the set of instructions loaded into memory and being ran by the processor.
A single program can spawn multiple processes, if wanted. For example, you can execute a text editor multiple times, where each instance of it will be a process.
A process then, can spawn multiple Threads to do the work it needs to be done.