You can't make one, Sims only become a ghost when they die.
You can, though, kill off your sims to "make" ghosts. A few ways to do this. Without cheats, you can easily drown them, or kill them with fire, or starve them. Old age will do it, too. To drown a sim (and I already know, it's "mean", according to my kids...), have them swim at home, so you can enter buy/build mode. Once they are swimming, delete the pool ladder(s). Eventually, they will tire and drown. (For TS3, you have to wall the pool, because they can climb out.) For a fire, no fire alarm, first off. Then, just have them walk away from cooking, so a fire starts, and delete (or lock) the doors so they can't get out. It's a bit violent, but makes a red ghost. Starvation, just isolate them from food. Old age, time will take care of. Oh, you can electrocute them, too, though that is harder. have a sim with no mechanical skill stand in water (maybe from a leaky sink...), and try to repair a television or whatever with the red skull on the back. They might just get a bit fried, but they can die this way. tedious, though. Satellite, they have to watch clouds like FOREVER. Lightning, play in a thunderstorm, and hope for the best. You get the idea.
With cheats, some other methods. First, in the neighborhood, turn on cheats. CTRL+SHIFT+C, then enter, exactly (without the quotation marks)
"boolProp testingCheatsEnabled true". Then enter the lot where your victims, er, sims, are living. Hold SHIFT, and while holding, click on a sim, and choose SPAWN, then Rodney's Tombstone of Life and Death. Then, for any sim on the lot, select that sim, click the tombstone, and choose the method. Any method available in game should show up. Those listed above, hail, lightning, satellite, electrocution, etc. With a littlw work, you can make enough ghosts to populate a whole cemetery. If that's the goal, do it all on ONE lot, save each time you kill the last sim, and bring in the new ones. Once done, move in lucky sims, and have them move the tombstones/urns, to your chosen community lot (preferably a cemetery one that you make for the purpose). They can move them all at once by clicking one, and selecting "move all graves", then the menu with the lot choices pops up. You can't kill babies or children, though teens are fair game, and pets can ONLY die of old age.
simple. You sell the grave stone. Or, you might be able to put them inside a gated fence, and lock the fence when all the grave stones are in it. Its worked for me.
Once they die, you can continue to play with that sim if they are the only sim on your lot. They will become ghosts.
Delete the tombstone.
Usually a ghost haunts you because you have it's grave on your property. Try moving it onto a graveyard.
The third ghost is your maid in the Espiritu Estate, you can't get rid of her yet but once you've completed the entire game. you can get back to her a see what she wants or needs. it might take a while to complete the entire game and to get rid of her.
They come back as a ghost when they've been mourned by the Sims who knew him/her.To get rid of the ghost, I THINK deleting their tombstone/urn will work. Also, stop mourning. (Might take a while, but they go away eventually.)
No, in the sims 2 Free time your sims can not get married to a ghost.
No, that comes in the Sims 3, but there is a ghost hack found in sim2wiki
I dont have sims pets (I have the sims 2 and seasons) but it's really easy to. go into buy mode and delete the grave! But if you want to keep it and dont want the ghost to come either keep your sims doing stuff so the ghost cant scare them or you can lead dem into a room and delete the door. The ghosts cant go thrugh apperantley. Then wait till daytime and the ghost will be gone.
your sims has to be a vampire and die of thirst. or you can get an orange ghost by dying in a fire.
You can't play as a ghost, they are not controllable.
There is no such thing as the ghost world.
no you cant become a ghost in the sims 1. If you die there only comes a thombstone that's all.
You cant have ghost babies anymore. They patched it.