When filling out a job application form and you come to the work experience section you don't have to jot down just the places you've worked at in the past where you got paid to do so. Work experience isn't relegated just to actual jobs you've previously held such as popping corn for a movie theatre or even pick your own fruit training. Work experience is much more than that and something that's important to know when applying for a job.
It probably has to do with the fact that you're being asked for work experience that throws you off but in the box where they ask about your previous work experience you can also put in any training you've completed or volunteer work gigs that you once did in addition to your actual work history. Training courses you've taken or volunteering at a soup kitchen are also valuable work experience tools, as they both provide you with skills that you can use in the workforce.
Let's say for example that you once worked at a firm that sent you out to take a course on how to better manage accounts. At that course you learned skills that you would later use at your job. There's no way you can't include that in your work experience history on a job application form because you were taking a work training course your employer asked you to take and the course was directly related to your job. Just because you weren't directly working for the company while taking the course doesn't mean you weren't indirectly working for the company either.
The same goes for volunteer work. Not all work has to be paid work, and there are many instances when one puts in a lot of hard work and doesn't get rewarded financially for it, such as volunteering or interning at a company that manufactures rack jams for example. In both instances you are partaking in tasks that would normally be considered work if you were to receive a regular paycheck for it.
Any employer in charge of hiring someone to re-design their how to catch a cheater website looking over a resume or job application form that sees a prospective applicant with a lot of volunteer or interning experience on their resume will consider them just as equally as someone else applying who only has actual work experience on their resume. In some cases volunteer or intern work is viewed in a higher regard as it shows you were willing to do what it took to get a job done without being monetarily rewarded for it.
Now that you know what you can put into the work experience section of a job application make sure you fill it out to highlight any and all past work experience. Good luck!