When filling out an employment application, it is always best to be honest when informing a potential employer about previous jobs. When double checking your employment history, an employer will not look favorably upon misinformation on this aspect of your application.
Usually you want to list previous employment where you've held a similar position to what your apply for. List any honors or awards you have received and skills which are used while working. If you haven't worked for awhile you can state you were not employed due to being i. e. a full-time student.
You need to list your previous jobs and probably the reason you don't work there anymore. This shows your experience and your work history whether it be negative or positive.
First you should always be completely honest. Give names, numbers, addresses, as well as what your duties were. Also, no matter what it was, give the actual reason for leaving.