A bit is a one or a zero. One is switch “on”. Zero is switch “Off”. It’s the binary system, the language of computers.
A byte is a group of 8 bits, so it’s some combination of ones and zeros.
Internet speeds are given in bits per second.
So if your ISP provides you a download speed of 60 megabits per second, you’re theoretically receiving 60 million ones and zeros each second, which your computer or phone can read as text, sound or video.