The first step to interviewing is getting noticed by those doing the hiring. That means you have to fill out an application or do provide a resume.
Most everyone will require some sort of application. The Business Insider gives great insight into how to get noticed on your job application. Click Here to check it out.
In the past Resumes were a must. To be honest, when I am interviewing people I rarely read their resume. Having said that, if a brief glance at what they submit looks unprofessional I won’t give them an interview. It is mostly about making an effort. Click Here to read a great article from Glass Door about how to write a perfect resume.