It is leaning because it is not getting enough light: succulents in low light become etiolated = stretched. They grow weak and skinny stems that can't support themselves. Some succulents will grow longer stem, but those, if in proper light, are sturdier.

It could be cut almost anywhere. I would cut it leaving maybe 1 leaf on existing stem and leave that stem potted - it may grow some offshoots. Cut off portion needs to be left to callus - dry up, and after potted. Do not water for a while; if there are no roots plant can't take any water in. You need to supply more light for your plants, or they will just keep growing same way.

If I could comment on your soil: it looks water retaining. It should be mixed with lots of perlite or pumice. What kind of soil is it?

...and I spy that they're sitting in water, they shouldn't be doing that. If you've just watered, it should be tipped away or set them on some paper to absorb any excess, but allowing them to sit in a permanent puddle isn't good practise :-)

Gill

To Rina: thank you for the advice !and the succulents are getting constant sun all day but I have them on a window sill so they are only getting it from one direction

To Gill: thank you for the advice! Also the plates have a glossy finish on them which I could see being mistaken for water