I think most of us use an Excel type spread sheet...
...Over the years, mine has become pretty elaborate including a trend line chart, weekly win/loss bar charts, end of week bankroll balance chart and cumulative win/loss bar chart, in addition to the usual numerical and comments on the spreadsheet.
The charts are fun, but not really necessary. More to keep me interested than anything else and pull me out of the doldrums when things are not going my way.
Cobbson