Splatoon 3 will offer a feature that is more or less standard in the online action genre today, which is customisable banners. This was introduced in two tweets from Nintendo UK, where they also explain that these banners will sport your very own title.
Those words are selected from a list though, unfortunately, rather than offer people to choose whatever they want. You will get access to more words by playing though.
Splatoon 3 launches exclusively for Switch on September 9.