How many books did Paul write to the churches?

The 'books' Paul wrote in The Bible did not contain 'prayers', but were actually letters, handwritten, to the congregations and to individual people, filled with encouragement, instruction, discipline and suggestions for the recipients. (2 Peter 3:14-16) Letters were the primary form of distance communication in Bible-times, in both the 'Old Testament' and the 'New' ( 2Samuel 11:14; 2Kings 5:5-7; 10:1, 2; 2Chronicles 30:1; Ezra 4:7; Isaiah 37:14; Jeremiah 29:1; Acts 9:1, 2; 28:21; 2Thessalonians 2:2; Hebrews 13:22 ) and letters from those taking the lead in the early Christian organization helped to keep the congregations clean and unified(2Corinthians 7:8+9; 10:8-11/Acts 15:22-31; 16:4+5) as they were forwarded and shared with all the congregations (Colossians 4:16; 1Thessalonians 5:27)(1 Corinthians 1:10).