There are three types of domains:
Generic or gTLD (generic Top Level Domain): they were the first ones that were created, in the beginning they were assigned according to the purpose that the web would have, for example .com for commercial websites. Currently they no longer have restrictions. Examples: .com, .org, .net, .info, .biz and .pro.
Territorial/country domains or ccTLD (country code Top Level Domain): they are reserved for countries. Examples: .es, .fr, .it, .mx, etc...
New domains or nGTLD: new extensions that have been created in the recent years to add more value to the domain name. Examples: .store, .football, .lawyer, .online, etc...