Strong's numbers

χάρτης (G5489)

chártēs

khar'-tace

from the same as χάραξ; a sheet ("chart") of writing-material (as to be scribbled over):--paper.

χάρτης, -ου, ὁ [in LXX: Is 8:1 A, Je 43 (36):2, 6, 23 (מְגִלָּה) * ;]

a sheet of paper, made of papyrus strips (v. Kennedy, Sources, 42; Milligan, NTD, 10-12; DB, iv, 945 f.): II Jo 12 (Plat., Inscr.).†

From G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922), in the public domain.

Shown in the King James Version (KJV), whichever translation you read in — it is the text these numbers are tagged against.

2 John 1:12
Having many things to write unto you, I would not write with paper and ink: but I trust to come unto you, and speak face to face, that our joy may be full.