"Early Christians used papyrus paper for their letters, scrolls, and codices. It also played an important part in the production of Bible manuscripts, until it was replaced by vellum (fine-grained animal skin) in the fourth century C.E. At 2 John 12, the apostle wrote that he would rather convey his message “face to face” than with “paper and ink.” Here the word “paper” translates the Greek word khar´tes, which is said to mean a sheet of paper made of papyrus. "Skins of sheep, goats, or calves prepared for use as writing material. Leather was long used as a writing material among ancient people; the Dead Sea Scroll of Isaiah, copied toward the end of the second century B.C.E., is of leather. Papyrus from Egypt became a more widely used writing material but, according to Pliny, when the ruler of Egypt prohibited the exporting of it about 190 B.C.E., the use of leather parchment was invented in Pergamum. (The English word “parchment” comes from Lat. pergamena.) Perhaps this means simply the popularizing of an already-existing method of treating the skins so that both sides could be written on. Scrolls of parchment were much more durable than the less expensive papyrus scrolls." At 2 Timothy 4:13 the apostle Paul asked Timothy to bring “the scrolls, especially the parchments.” (NW, Ro) He does not indicate the contents of these requested items, but quite possibly he was asking for portions of the Hebrew Scriptures so that he could study them while imprisoned in Rome. The phrase “especially the parchments” may indicate that both scrolls of papyrus and scrolls of parchment were involved. Some quotes from the publication "Insight on the Scriptures" Volume II, Watchtower Bible and Tract Society.

what else did they use to write the bible?

He was a pioneer, so I suppose he must have had an I-Mac.