If they ask for proof of experience, make sure you can show them.
Here’s some entertainment industry jargon I heard once: if you want to get a part, be it in a show, a movie, or even just a commercial, you need tape. “Tape” is a catch-all term for proof of your work. Studio productions won’t hire an actor if they don’t have tangible proof of them acting in a professional capacity. “Tape” is a term I’ve co-opted when talking about work experience in general, because it’s a fitting term; if you don’t have visible proof that you’re capable of what you claim to be, no one will take you at your word.
When you’re applying for a job, any online application will ask you for your experience in that particular field or with a particular skill set. Usually it’s just a matter of saying how long you’ve been in the game, but nine times out of ten, a recruiter won’t just leave it at that. Any Joe Shmoe can say they have years of experience, but the proof is in the pudding. This is why you need a source of tangible evidence.
If you’re in a writing-centric field, for example, you need to assemble a portfolio. This can be a PDF of links to your published work if you want to keep it simple, or if you want something a little more attractive, you can make a simple website to host content/links through a service like WordPress. If you’ve created a large amount of content, then you don’t need to list every last thing you’ve ever made. In fact, you shouldn’t; unless your name is Elvis Presley, no one is going to spend all day browsing through your museum of accomplishments. Pick and choose a few standouts that you feel exceptionally proud of. This same advice can apply to any content creation-based field, like art or music.
Some job applications also offer practical tests you can use to demonstrate your expertise. These are great if you work in a field that’s harder to keep tangible proof of. Even if an application doesn’t offer one, there are outside tests you can take and save to have as a record of your chops.
No one in any industry will take someone purely at their word. If you can show a record of your skills and accomplishments, you’ll become much more attractive as an applicant.