I got a usb because my macbook hates storage (even though it should have a bunch of free storage). It won't let me download anything to it nor does my laptop use the new storage at all. I've tried changing the format of the usb, but that didn't work so I'm at a loss.
[Re-Titled by Moderator]
MacBook Air 13″, macOS 10.15
Sounds like you bought an external USB hard drive or SSD that was formatted using NTFS – a Windows filesystem. macOS can read NTFS volumes, but cannot write to them without the aid of third-party filesystem drivers.
For a drive that you are going to use with a Mac, the normal fix is to go into Disk Utility and reformat the drive either as APFS or as Mac OS Extended (journaled, non-case-sensitive) (a.k.a. the most common form of HFS+). It sounds like things failed at that stage – so what error message, exactly, did you get?
USB flash drives are normally formatted using FAT32 or exFAT, which Macs can read and write out of the box.
USB drive won't work on my MacBook Air
