There are a lot of apps and websites that have sudoku puzzles. There are even handheld devices specifically made for solving sudoku puzzles. There are good reasons for solving on paper and also good reasons for solving on a computer. Each way has its own pros and cons.
Solving sudoku puzzles on paper allows puzzle solving anywhere. A puzzle and a pen or pencil are all that is needed. Sudoku puzzles can be found in newspapers, on airplanes, on cruise ships and many other places. Books and magazines are available with a virtually endless supply of puzzles.
With software things can be done that can’t be done on paper like auto-filling candidates and giving hints about what the next move could be. Software can check numbers already entered and warn about mistakes. With computer apps and websites there is virtually an unlimited supply of different puzzles to be solved at all skill levels.
Sudoku - the puzzle that addicts