If you want to change settings on your Factorio server, you can use these steps to edit each config. It's important to note that you cannot change world and generation settings after starting a game and you will have to start a new world.
1. Open the File Manager
2. Navigate to /config/
3. Here, you'll see all of your config files.
4. map-gen-settings.json
contains settings for things such as cliff elevation, resource frequency, difficulty, starting area, and the world seed. Changing this file will require resetting the world.
5. map-settings.json
contains settings for things such as enemy behavior, pollution spread, more difficulty settings, movement, path finder settings, and asteroids. Changing this file will require resetting the world or it could risk save corruption.
6. server-settings.json
contains general settings for the server, such as who can run commands, if the server pauses when no players are online, afrk kicking, autosaving, and more. Changing this file will not require resetting the world.
If your settings require starting a new world, you can use this guide to do so.