The name can consist of roughly 15 lower case letters or 10 upper case letters. You can enter letters, dashes, full-stops, numbers and special characters like emojis. You can also use accented letters like "è". (You can't put accented letters on ios devices or the name will be blank.)
How to change a cat's name:
Now you should be on this screen ->
First of all have a think about what adorable name your Cat is going to have.Then all you need to do is press the white bubble at the top where the name "Snowball" for example is presented. That will open a section where you can type in a name from your keyboard. Press submit and there your new name should be.