Email resume/cover letter or use website

Is there a preferred method to apply for this listing? Or more or less, what would be the best route to go?

This listing states

If you are interested in applying for this position, please email a resume and cover letter to hr@companyname or simply apply online below.

Screenshot of apply online feature

Seems trivial but what the hell do I do with the comments box? Would that supplement my cover letter?

I miss college.

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