Laptops now pretty much always use an SSD for data storage; they're way faster than an old mechanical hard disk drive. As with RAM, buy the largest capacity you can afford. However storage can be easily increased after purchase with one of the best external hard drives or best portable hard drives.
The only thing to bear in mind with this upgrade path is the speed and extent of your laptop's connectivity. Generally most new laptops will have at least one USB 3.2 / Thunderbolt 3, or USB 4 / Thunderbolt 4 connection. Either will be plenty fast enough to run an external hard drive to the max. Generally, the larger the laptop, the more physical USB ports it'll have. That's useful when connecting multiple peripherals, like an external keyboard, mouse and secondary monitor.