Once the data is secured, the method of clearing the drive depends heavily on the hardware itself. Modern laptops generally utilize one of two types of storage: Hard Disk Drives (HDDs) or Solid State Drives (SSDs). An HDD uses spinning magnetic platters to store data. To clear an HDD securely, one must overwrite the data with zeros or random patterns so that the original magnetic traces are destroyed. This is often done using specialized software like DBAN (Darik's Boot and Nuke), which scrubs the drive to Department of Defense standards.
Would you like a step-by-step guide for your specific laptop model (Windows or Mac, HDD or SSD)? how to clear a laptop hard drive