Martha Kent and Jonathan Kent, also known as Ma and Pa Kent, are a caring couple in Kansas. The Kents are the adoptive parents of Superman. They live in the small town of Smallville, Kansas. The couple is usually portrayed age-wise as either late middle age or elderly.
In most versions of Superman's origin story, Jonathan and Martha were the first to come across the rocket that brought the infant Kal-El to Earth, with their adopting him shortly thereafter, renaming him Clark Kent - "Clark" being Martha's maiden name.
The Kents are usually portrayed as caring parents who instill within Clark a strong sense of morals, and they encourage Clark to use his powers for the betterment of humanity. Martha is also the one who creates Clark's superhero costume.
Lana and New Earth Jonathan Kent also shared a father and daughter like relationship. Jonathan died from a heart attack in this universe. Lana was seen grieving his passing at his funeral.
Smallville Universe: Martha and Lana were very close; in fact, they shared a mother and daughter like relationship. However, Lana and Jonathan did not share a similar relationship; he cared for her deeply and vise versa, but they were never very close. This Jonathan also died from a heart attack; she was also seen in attendance at his funeral.
Prime Earth: In this universe Martha was killed in a car accident on Clark and Lana's senior prom night. Jonathan died a few days after Martha from injuries he sustained in the accident. Lana attended their funeral with Clark.