If you have a laptop made between approximately 20 and it doesn’t contain a 2.5-inch hard drive, you may need an mSATA drive. mSATA SSDs look a bit like shorter, wider M.2 drives.
M.2 SATA SSDs used to be good budget options for any computer with an M.2 slot, but modern NVMe drives cost roughly the same and perform much better-use an M.2 SATA SSD only if you have to. M.2 SATA SSDs use the same connector as M.2 NVMe SSDs, and some computers that can use NVMe drives can also use M.2 SATA drives.
SATA (which refers to both the connector type and the interface protocol, in this case) is older and slower than NVMe, but SATA SSDs are still noticeably faster than SATA hard drives, and they’re a worthwhile upgrade for most computers built after 2011 or 2012.