When choosing cat food, we might feel confused having so many options out there to choose from. In short, you should select one complete dry food and one complete wet food that is adequate for your cat's life stage: growing if it is a kitten, adult, senior, etc.
A general recommendation is to offer approx 50-66% of wet food and 50-33% of dry food, divided into small but frequent meals.
Offering, for a few days, the same food that s/he is eating at the moment, and start weaning it progressively to the diet that we have decided, is a safe option to avoid gastrointestinal problems such as vomiting and diarrhea. It is also a way to make the accommodation process smoother for our cat keeping some familiarity between so many changes.
Cats are not good drinkers, but we need to offer water available to drink all the time. To encourage them to drink, we should separate water from food and other resources such as litter boxes, beds, etc. Also, we can offer a cat waterer like Kittyspring that can provide clean water for 2 long days because clean water tends to be more appealing for cats.