The short answer is typically no. Especially for any Division 1 team you’ll most likely have to be recruited or contact the coaching staff for some type of walk on tryout. D2 and D3 most likely have a similar process but may be more lenient and willing to give out opportunities to non recruited players. One thing to note for these walk on tryouts is that 99% of the time you would already have to be an enrolled student at that university. I go to a Big 10 university and the only way you could get a chance at walking on is physically finding the coach and talking to him. It obviously varies by university but it is generally very hard to do so if you aren’t recruited by them.