In the companies I have worked for there has been a bonus offered if an employee makes a recommendation and the person ends up accepting the position and work for a period of at least 6 months. The key is that the bonus is only available if the resume has not already been in the system.
The goal of the program is to capture new resumes. There doesn't seem to be any weight assigned to the resume because of the recommendation. I have recommended people that never got an interview, and others that did get interviews. The automatic filters were still used, and HR still narrowed down the number of candidates.
Now in smaller companies there are not as many automated systems. They may use a 3rd party company to gather resumes, but will also accept them directly from employees. In that case getting the resume from a employee can still be a very good thing. There is no way to know if getting it from two source confuse the issue if they ow a finders fee to the recruiting company.
In the larger companies the employee when they make a recommendation fills out the info on an internal website, uploads a resume; and that creates a profile for the candidate. The candidate is then sent an email inviting them to complete the profile, and then apply for one or more positions. If the candidate already has a profile, the email is sent asking inviting them to apply but the employee doesn't get credit for the recommendation.
It is sometimes better to look for connections before applying.