An Internet domain is the name that will be used to access your web page or email, among others. To create a web page, you will need a domain and web hosting where the content of your page will be stored (texts, photographs, etc..)
Register your name on social networks to reinforce your brand and prevent others from appropriating it.
A trademark gives the exclusive use of a name in the requesting country. Besides names may also be registered phrases, pictures or designs.