Did john Lennon or paul McCartney ever write a song for someone else to record?

Yes, both John Lennon and Paul McCartney have written songs for other artists to record. Here are a few examples:

John Lennon:

"Instant Karma!" (recorded by Yoko Ono)

"Real Love" (recorded by the Beatles)

"Jealous Guy" (recorded by Roxy Music)

"Woman" (recorded by Peter & Gordon)

"Mother" (recorded by Plastic Ono Band)

Paul McCartney:

"A World Without Love" (recorded by Peter & Gordon)

"Step Inside Love" (recorded by Cilla Black)

"Goodbye" (recorded by Mary Hopkin)

"Come and Get It" (recorded by Badfinger)

"Mull of Kintyre" (recorded by Wings)