Your main contact within the company will depend primarily on the size/structure of the company and your career focus. For those companies with large, well-established entry level hiring programs, there may be one or more persons focused solely on hiring you, the college student. This function is covered by a "College Recruiter" or "College Relations Representative" who is usually part of the Human Resources Department. This is the person responsible for on-campus recruiting. This is the person whose job it is to screen out and disqualify. To pare down the long list into the short list.
It's easy to identify areas where you fall short of the defined standard. Your job is to find the areas in which you excel.
The College Recruiter's criteria may be limiting—even to the point of counting you out before you even get in the door. Your main objective in making any contact should be to secure an in-person interview. And you cannot accomplish this if you are screened out. Why would you be screened? Most common is the school you attend. "It is not on our list." Or your GPA. "Too low for our standards." Or your major. "We are not hiring any of those this year." Or timing. "We have done all our entry level hiring for this year." Rather cold, but it's the reality of the typical College Recruiter. You may get nothing more than "what is on the board" of current entry level needs to be filled. But do not consider it the end of the line. The true bottom-line decision-maker is the Hiring Manager, typically the line manager in the department that is hiring. Establish the College Recruiter as your target contact only as it serves your needs. Once it becomes a dead end or point of no further progress, you should be willing to immediately move on to the Hiring Manager as your target contact.
While it is almost always more difficult to locate and contact the Hiring Manager than to simply make contact with someone in HR, in the long run it pays to put forth the extra effort. Contacting HR is what everyone does. So if you do the same you merely join the competition in targeting a department whose primary task is to screen you out—and your odds for success will likely be quite low. But direct contact with the Hiring Manager is golden. You are actually talking to the person who can hire you.
Hiring Managers determine hiring needs. Hiring Managers have the most latitude in determining what background will adequately fill the company's needs. And it is Hiring Managers who have the actual authority to hire.
Make the Hiring Manager your ultimate target contact. And do not give up easily.