There are many ways to “log” your contacts, paper logging, software logging or on-line logging sites typically a combination of these is the latest method. For contesting you will usually be required to submit a log (in Cabrillo format) to the sponsor of a particular contest, an example is to the ARRL for their “ARRL Field Day” (not a contest?)
There are many software programs that log your contacts, will create a Cabrillo file and may even submit it directly to the proper sponsor.
Ham Radio Deluxe
Logging with N3FJP
N3FJP (far more than just logging software) Use the AC log offered within the N3FJP software package or purchase it separately.
Ham Radio Log Software : Log program for ham radio log books software (dxzone.com)
Log Book Of The World
XMLog – Amateur Radio Logbook System
This is merely a short list, I will keep adding to this page as time permits, for suggestions, complaints, rants etc. email me at firstname.lastname@example.org