Link to the Marvel Encyclopedia*
*(it's probably outdated!)
A website I would recommend for starters (or for longtime fans) is Fandom Wiki's Marvel. It's absolutely jam-packed with tons of information regarding Marvel.
Another—slightly more credible—website is marvel.com. It's straight from the source and has the most accurate Marvel-related info.
Background image from Etsy
By Sophia Doshi
After I had flipped through a couple of the pages, I realized that this was fascinating. I wanted to know everything about all of the characters and their stories. I ran to my father and shoved the book in his face, bombarding him with questions about it. A smile soon broke across his face when he realized that I was interested in Marvel. He explained what Marvel was, how he grew up with it, and how he was excited to learn that I was interested in it as well. He lent me a few comics from his own childhood and encouraged me to flip through them. I accepted them excitedly and immediately sat down to read them.
I spent the remainder of the day flipping through the comics, concentrating hard on jumping from panel to panel, trying to take in all of the characters and how their stories were playing out. I tagged Spider-Man and Black Widow as two of my favorites early on; the lit would eventually evolve to include Captain America and Mystique. The comics were fascinating to nine-year-old me, but they were hard to read—the colors and placement of the speech bubbles became overwhelming. I ended up closing around what seemed like the sixth comic. Three hours really had my brain feeling spent. Regardless, my dad looked on with pride in his eyes when he realized who I was going to become: a Marvel-loving menace.
Cover image from WallpaperCave