All data in a computer is stored through a binary electrical system – binary as in bi, two. The bit, the computer’s unit of data, is expressed through an electrical signal or the lack thereof. This signal is managed by a transistor, a tiny switch that can be activated by the electrical signals it receives. If the transistor is activated, it conducts electricity. This creates an electrical signature in the computer's memory equivalent to a 1 or a truth. Otherwise, the lack of signal is equivalent to a 0 or a false.
The basis of this binary system, as we have it today, was first introduced by Leibnitz in 1689, as part of an attempt to develop a system to convert verbal logic into the smallest form of pure mathematics. It is said Leibnitz was actually influenced by the i-Ching 🤯 and was attempting to combine his philosophical and religious beliefs with the field of mathematics. Together with George Bool’s work in logic and MIT’s Claude Shanon paper relating them to computing, this was basis for the simple and yet incredibly ingenious system behind today’s digital computer.
There have been ternary and even quinary electrical systems developed in the field of computing. But the more complex the system, the harder it is to tell the difference between different types of voltage; specially when the computer is low on battery or its electrical system interfered with by another device (i.e. a microwave). So the world settled on binary, the simplest and most effective system. The voltage is either there or not.
That's how we get zeros and ones: electricity.