Ask HN: What's the best online method to contact a company?

You would need to go through their careers page and follow the listed procedure or a recruiter for the company if they do not have a careers page for applying for a job. Even if you know someone who works for the company you normally still have to go through the formal process of applying for the job.

If you have met with someone that has suggested you apply for a job, especially someone in the top brass of the company they will normally have their HR team create a job listing with a specific requisition id or jobid for you to specifically apply to. You will apply and still go through the hiring process and interview but you may or may not already be pre-approved (normally they will not let you know this in advance so you still go through the procedure like everyone else (nervous interview or interviews or great to watch and are still a good step to help insure you have what it takes even though you may already have the job before applying for it).

You may also see some companies that want you to just email your resume or use their contact page. Be sure to read the instructions as some tech companies want you to just email them your resume in all text (no word, pdf, etc.)