I want to put my dog to sleep because she is old and is losing weight where do I go

So sad 😢 I myslef had to put my dog to sleep before very hard to do but had to be done.

Call your vet, putting a dog down because it is old I can't agree with but if they are losing weight there maybe some underline condition.

as John and Bret have said, call your vet

Lila, seeking out a veterinarian in this instance and for this purpose is always best. However, if the dog is really suffering you can take it to the Humane Society and abandon the dog and of course they will have to put the dog to sleep. That's not a great choice but as I say if your friend is really really suffering some people do have to go that route. It's always sad to part ways with our furry friends. God bless and good luck

Call your vet for help on this.