The farthest planet in the universe that we can see depends on various factors, including the sensitivity of our telescopes, the planet's distance from Earth, and its reflectivity. our current technology and observational capabilities allow us to detect and observe planets within our own galaxy, the Milky Way.
While we have discovered thousands of exoplanets (planets orbiting stars other than our Sun), most of them have been detected through indirect methods, such as measuring the slight dimming of a star's light as a planet passes in front of it (transit method) or detecting the wobbling motion of a star caused by the gravitational pull of an orbiting planet (radial velocity method). These methods are more suitable for identifying planets closer to their host stars rather than distant planets.
Directly imaging planets is a challenging task, and currently, our telescopes are not capable of resolving individual planets located in other galaxies. The vast distances between galaxies and the limited light-gathering capabilities of our telescopes make it extremely difficult to observe individual planets outside our own galaxy.
It's worth mentioning that the universe is a vast expanse, and there are likely countless planets out there, but our current observational technology has limitations that restrict our ability to directly observe them. Future advancements in telescope technology and observational techniques may enable us to detect and study planets located farther away in the future.