ender dragon is a final BOSS, you have to go into the end which you can get in with end portal which needs enderpears, these end portals are located in stronghold which is far from the spawn location

How to beat Minecraft (this starts from getting the ender pearls and blaze rods):
1) Go to the Nether. And get a lot of gold ingots.
2) Go to a piglin group.
3) Trade with them. Throw some gold here and there. You’ll get ender pearls (which is required).
4) After you get 16 ender pearls, go to a nether fortress.
5) Look for blaze spawners and kiil the blazes, don’t break the spawner.
6) After you get 8-10 blaze rods, you can return home.
7) Craft 16 eyes of ender.
8) Find a stronghold, it’s 2000 blocks away from spawn, mostly.
9) After you found it, go to the portal room. Destroy the silverfish spawner.
10) Put the ender eyes on the portal frame.
11) Beat the ender dragon (Using beds and axes are the best. But I used guns).
12) Boom, you’ve finished Minecraft.