my question is pretty much in the title and i mean in "habitable planet" like earth, but not necessary to be same size or content.
so i was thinking rather than finding habitable planet which probably contain extraterrestrial lifeform already, and can possibly bring many problem from invasion/war,unknown space disease like from "war of the worlds movie bacteria stuff" or like the first contact with native people,political or social like living together with this extraterrestrial that require adaptation either culture or the land itself,the colonialism stuff.
and finding suitable planet to terraform is quite a gamble need thorough research and require different formula or material for the terraform.
why not just make the planet itself from accumulating compressed human excrement and just bring it to the suitable orbit or star and start terraforming, at least with this i believe the formula or material require would be the same, while also can be mass produce if human need new land, also i believe finding suitable star is more easy than suitable planet with different distance.
here some example visual spaceship from starwars (not necessary to be round shape so dont take it to literal) with my paint to point the core or the inside that contain compressed human excrement, with the outer layer can be stretch or expand to give room if it out of capacity and can be split like egg or scater into smaller ship to let it out so the ship can just focus to keep moving to their destination while the human excrement can accumulate or produced and i assume the human excrement can give methane as an extra fuel.
i believe maybe it can be made from accumulating asteroid too but i think it require to mine the asteroid and its a moving object so it will need the ship to follow around while full of danger from flying debris or another asteroid also i think asteroid is mismatch of many mineral wth different hardness its probably hard to compress without endangering the ship.