Most auditions are online now. You will need to familiarize yourself with all the sites that casting directors use. You will need to upload your headshots, resume, and reel to these sites and pay membership fees. Most casting sites have reasonable fees.
Actors Access is the main website used for casting theatrical film and TV. There are also commercials, short films, students films, vertical short form, and theater listed there. actorsaccess.com
Instructions of how to add your profile actors access: FAQ
Other acting sites to add your acting profile to are commercial casting sites that sometimes list other types of roles: castingnetworks.com and castingfrontier.com.
It is also good to have an acting profile on IMDb.com to add films and shows you’ve done. When you create a profile there and have a membership you can also access agents, managers, and casting directors contact information if they have it listed there.
Once you have your acting profiles created you can start submitting to casting notices listed in your area or other areas you can travel to. If your submission is selected you will likely receive an “ecocast audition” This is an audition you self tape for and send in through actors access or the other site depending where the audition came from. You could also receive an invitation to a zoom type live audition.
Be weary of casting notices listed in other places like Facebook or craigslist!