How can I find reputable literary agents who accept free submissions?

I am a new writer currently working on my first novel and I feel completely lost about the publishing side of things. I have finished a rough draft of my manuscript and I am now looking for guidance on the next steps. Can anyone here tell me where and how I can find reputable literary agents who accept submissions from debut authors for free and online? I do not have money to pay for services and I want to avoid scams. What websites, databases, or directories are safe to use for agent research? Also, what is the standard process for submitting a query letter and manuscript online? Do most agents use QueryManager, email, or their own portals, and are there any specific formatting rules I should know before I send anything out? I would really appreciate detailed advice from writers who have gone through this process before.