Can you make a seed? [closed]

I think you are asking "Can you design a world seed so it produces a world the way you want it?" The answer to this question is no.

What most people do is discover a seed. They start a game (either typing in a seed or letting the game generate one randomly) and then get to looking around and realize that their world is pretty awesome. Whether they "guessed" at a seed or allowed the random generator to do its thing, they can now look up their world's seed (and starting settings) and share that information so that other people can generate their same starting world.

Only the starting world generation can be shared via a seed, not any changes you make (in the game or by using a mod or program). Also remember that for a seed to work, other players need to be using the exact same generation settings as the seed's discoverer: things like difficulty or resolution don't matter, of course; but things like "Superflat" and "Generate Structures" must be set the same, and any mods that change world-gen (by adding new biomes or ores or plants or basically anything that spawns in the world instead of being crafted by the player) will completely invalidate any seeds discovered without using those exact same mods.