The first general-purpose programmable electronic computer is widely considered to be the ENIAC (Electronic Numerical Integrator and Computer).

The ENIAC was developed by John Mauchly and J. Presper Eckert at the University of Pennsylvania and was first operational in 1945.
It was designed to calculate artillery firing tables for the United States Army during World War II.

Key characteristics of the ENIAC include:

• Electronic: Used vacuum tubes instead of mechanical relays.
• Programmable: Could be programmed to perform different tasks by rewiring and reconfiguring its components.
• General-Purpose: Capable of solving a wide range of numerical problems, not just specific calculations.

While there were other computing devices before ENIAC, it is recognized as the first electronic, general-purpose, programmable computer.

More information can be found on the Britannica website.