There are a few ways you can apply for digital jobs, depending on the company you're applying to. If you're applying online, most companies will have an application form available. You might also be asked to send in your resume and cover letter separately, or to complete an online questionnaire.
If you're applying in person, be prepared to give your name, address and phone number (so the company can contact you if they're interested in talking with you), and dress professionally. Some companies prefer candidates who have job offers already lined up, so don't bother applying if you haven't been offered a position yet.