Your baby is probably suffering from a gut infection- usually viral in this age group.
There are no magical remedies to stop the loose stools immediately.
Just be sure that she is drinking well and passes urine atleast 4 to 5 times in a day.
You may give her fluids like plain water, vegetable soups, rice based porridge, soya milk along with Pedialyte
Plenty of curds will help her as curd has probiotic
bacteria naturally that helps in reduction of frequency and duration of loose stools.
Boiled potato, Banana will also help.
Its better to avoid cow`s milk, formula milk, fruit juices.
You may also give her Probiotic sachets like Econorm
in a dose of 1/2 sachet twice daily for about 5 days.
She will be okay soon.
At any time if she does not drink well/ urine frequency is less/ she is dull and activity is less/ she develops high grade fever/ you see blood in stools- then you must see a pediatrician
Hope my answer helps you.
Wish your kid a speedy recovery.