Your club's identity settings cover its name, its web address, a crest, and a primary colour. The web address is the URL slug people use to reach your club's page, and changes are checked live for availability just like when you first set it up.
Crest and colour are both optional. Leave the crest blank and Dugout generates a simple badge from your club's initials; leave the colour blank and your club uses the standard neutral theme instead of a custom one. Add them whenever you're ready. There's no requirement to have branding in place from day one.