My puppy is 6 mnth a yorky tiny teacup. When I got her 3 months ago she did not have bad breath. As of 3 weeks her breath is a little strong any suggestions?

Get her teeth and mouth checked. Perhaps her food needs changing. Bad breath can come from the mouth or it can come from the stomach. Is she breathing okay?

She could have a retained baby tooth that is rotting, usually it happens when they are a little older but it's a possibility.
Get your vet to check out her mouth, you might not even need an appointment, just drop in and hopefully one of the vet techs can have a quick look for you.

You can also start brushing her teeth. Start with a piece of panty hose, wrap it around your finger and lightly brush her teeth and gum. Once she is used to having your finger in there, you can actually purchase a doggy tooth brush and paste from a pet store or from your vet.