This is an emergency, so you need to get her to the vet.
If a cat stops eating for more than 24 hours it can cause fatty liver syndrome; this might be fatal in itself. And the illness that is the cause for not eating must be solved as fast as possible or your cat will die.
You need to call your vet to find the closest emergency veterinary service; where I live the vets are still open for emergencies but not for the regular services.
Source https://en.wikipedia.org/wiki/Feline_hepatic_lipidosis
This answer was made during the covid lockdown,most veterinary services have resumed normal operation by now.