Its 1/6 to roll a 7 with two 6-sided dice. You can get weighted dice that make it more likely to land on a certain number.
Does having one weighted dice change the odds at all? My gut says no but reality is a tricky bitch and I’m convinced im wrong somehow.
Your question is already answered correctly, so I’m just chiming in with thoughts on a similar situation :)
If you weigh both dice, it gets interesting again.
The obvious is to make one die roll always 3 and the other always 4, and get 1/1 chance of 7 but that’s boring and you’ll only get a few throws in before you’re obviously cheating.
Dice are arranged so that opposite sides always add up to 7, meaning you can get 1,2,3 around one corner and 4,5,6 around the opposite corner. So if you weigh opposite corners on each die, you get a 1/3 chance of rolling a 7 by varying combinatons. You might get away with a few more rolls like that.