The most popular setup is a combination, where the solid-state drive (SSD) boots Windows and most used applications, and the hard disk drive (HDD) is used primarily for mass storage.
An SSD (Solid State Drive) is flash storage and has no moving parts whatsoever. As a result, they’re smaller and take up less space in a computer, in some cases even mounting directly on the motherboard. SSD storage is much faster than its HDD (Hard Disk Drive) equivalent which is made up of magnetic tape and has mechanical parts inside. They’re larger than SSDs and much slower to read and write.
With a SSD, the waiting time is dramatically reduced, even on cheaper drives, when compared to HDD. Anything you load on it will perform actions much faster. However, with an HDD, you get mass storage and is much cheaper.