I have had many candidates ask me if i is ok to apply to multiple roles at the same company. The answer to that is yes and no. The first thing you should you should know about applying for multiple roles is that the company knows about it. As a recruiter, when we review applicants in the ATS (applicant tracking system), there is usually a drop down on each candidate that shows you what roles they have applied to.
So for example, if there are multiple roles in the Quality Assurance Department and you are a quality engineer, as long as you are qualified, feel free to apply to two or at the most three. This is reasonable and most recruiters and hiring manager will not hold it against you. Now if you apply to 10 or 15 roles it is safe to assume that you wont receive a call for any of them.
Even if you are qualified for one of the roles it is unlikely a company will pursue you further because when you apply to so many roles they wont consider you a serious candidate. Another thing you want to do is be upfront with the company that you have applied to. If you are in process for one role and a recruiter contacts you about a second role, make sure that you inform them of the situation. Often they will know this as most recruiters and hiring managers will communicate if they have interest in the same candidate for different roles.
The big take away here is that if you are interested in a company, you are doing a disservice to apply to as many roles as possible. You would be surprised how often this happens. Find the role that you are most interested in pursue that role. You will give yourself a much better chance at securing employment.