I was wondering how I could send a byte array of 16 or more bytes from the pi to a computer, where the computer would receive it via USB. Could UART send a byte array of this length? If yes, how can I arrange them? I have sent them over via wifi, using sockets on python, now I need to send them over USB, as it is faster and more reliable. Thanks! NB: I am using Raspberry Pi3, model B.
Yes you can.
Use a USB serial dongle. One end will be USB to plug into a USB port. The other end should be pins to connect with wires to the Pi's TXD, RXD, and ground pins. Make sure the dongle works with 3V3 TTL (i.e. can talk to the Pi GPIO).
The device will be seen as a serial device at the PC and Pi ends.