Comments are descriptive words or sentences, typically used as internal documentation in application programs. Comments are an essential part of application system documentation.

In Zim, the percent sign (%) is used to signal the start of a comment. When the software encounters the comment indicator, it ignores all subsequent characters on the current physical line as shown in the following example:

% An example showing the use of comments.
form set (not scroll) fPlayers % turn off scrolling
   when Event.EventName = 'F3' % Process Exit action
      return                   % Terminate the main procedure
   when Event.EventName = 'F4' % Process Update action
   when Event.EventName = 'F5' % Process Add action
        AddPlayers ( PlayersAdded)
   when Event.EventName = 'F6' % Process Delete action
        DeletePlayers ( PlayersDeleted)
   when Event.EventName = 'F7' % Process Report action

To use a percent sign as a literal character rather than as a comment indicator, enclose the percent sign in quotation marks.