During a part of the Main Quest you may be admitted solely because you are Dragonborn.

You must pass a magic test to enter, requiring you to cast one of five spells randomly. The College of Winterhold serves as Skyrim's Mage Guild You'll find more rewards along the way if you walk, especially Alchemy ingredients, but taking a carriage will allow you to quickly join any of these Guilds in Skyrim. Outside most Capitols' stables (like Whiterun), you can find a horse carriage that will take you to any of Skyrim's other Holds.

Traveling by Carriage is a fast way to join Guilds early in Skyrim You can expect minor spoilers, given knowing the rewards for joining may blunt a surprise. This guide will teach you where to get started and join each Guild in Skyrim and how they will help your character. Factions may offer skill trainers, special abilities, or material gain, while giving your characters unique quests to pursue that will help you explore new areas. There are several Guilds and Factions the Dragonborn can join or ally with, which offer their own unique rewards and benefits. Guilds of Skyrim How and Where to Join a Guild

Skyrim special edition guild starter