Archfey are known to take on other forms, for example Titania taking the form of a nymph, to have trysts with lesser beings.  Sometimes the offspring of these unions inherit a portion of their fey parent's power and their capricious/ whimsical personality.  Other times the offspring appears to be a typical member of a lesser fey or mundane race, but one or more of their descendants may manifest these fey traits.  Fey Soul sorcerers are often mistaken for bards or Divine Soul sorcerers with a creative streak.  The latter is understandable since the difference between an Archfey and a deity is in large part personality and acquaintances.

Fey Magic

Your fey ancestry allows you to learn spells normally associated with the bard class. When your Spellcasting feature lets you learn a sorcerer cantrip or a sorcerer spell of 1st level or higher, you can choose the new spell from the bard spell list or the sorcerer spell list. You must otherwise obey all the restrictions for selecting the spell, and it becomes a sorcerer spell for you.

In addition, you learn the Faerie Fire spell.  It counts as a sorcerer spell for you, but doesn't count against your number of sorcerer spells known. If you later replace this spells, you must replace it with a spell from the bard spell list.

Fey Guide

You learn the find familiar spell and can cast it as a ritual. The spell doesn’t count against your number of spells known.

When you cast the spell, you can choose one of the normal forms for your familiar or the following special form: sprite.

Additionally, you may spend your bonus action to allow your familiar to make one attack of its own with its reaction.

If any creature with 100 feet of you has the fey  creature type, for example your fey guide sprite familiar, they function as your arcane focus which allows you to ignore the requirement for material components that lack a cost and aren't consumed by a spell when you cast spells.

Fey Metamagic

Starting at 6th level, you innately know several new ways to use sorcery points that are unique to those with Archfey blood in their veins.  The maximum number of sorcery points that can be spent on an individual casting of one of the following fey meta magic uses equals half your sorcerer levels round up.  You cannot combine use of Fey metamagic in the same casting with the usual sorcerer meta magic.

Archfey Fire: this use of fey meta magic can alter the behavior of the Faerie Fire spell in a variety of ways.  Each of which costs 1 sorcery point to activate.

• Double the range and edge length of the cube area of effect (this can be activated multiple times in a single casting, each activation costs 1 sorcery point)
• Double the Duration (this can be activated multiple times in a single casting, each activation costs a sorcery point)
• Cast without having to concentrate on Faerie fire for the duration of the spell.
• Impose Disadvantage on the Dexterity saving throw to all targets in the area of effect.
• Exclude any desired subset of creatures/constructs/objects in the area of effect from being targeted by the spell.
• Dispell magical darkness.
• Whenever any target under the effect of Archfey Fire takes damage from any source they take an additional 1d4 radiant damage.

Archfey Step: this use of fey metamagic alters the behavior of the Misty step spell in a variety of ways. Each of which costs 1 sorcery point to activate.

• Leave the material  plane and fully step into feywild
• Turn invisible until the start of your next turn.
• Double the range of the misty step spell (this can be activated multiple times in a single casting, each activation costs a sorcery point).
• Cause the spell (and metamagic) to also apply to a number of willing creatures within 10 ft of you equal to your proficiency bonus.

 

Otherworldly Wings

Starting at 14th level, you can use a bonus action to manifest a pair of spectral wings from your back. While the wings are present, you have a flying speed of 30 feet. The wings last until you’re incapacitated, you die, or you dismiss them as a bonus action.

The spectral wings appear to be fairy/butterfly/dragonfly wings.

Archfey

Starting at 18th level, you have transitioned into a lesser Archfey. Your creature type becomes fey (this interacts with fey guide by allowing you to act as your own arcane focus) but you do not lose access to any of your feats that required your previous race.  However you no longer qualify for new feats that required your previous race.

Your overall appearance changes to resemble either an eladrin or fairy.  Your eyes glow with swirling iridescent colors.

You become youthful and slender.  Moreover you no longer age.  You become immune to magical aging, the charmed effect, and non-magical diseases.

As an immortal:

• you are no longer precluded from using spells above 9th level;
• you can use sorcery points to gain spell slots up to half your character level round up;
• you can exceed 20 characters levels by taking levels in different classes;
• if you have or take warlock levels, you become your own patron (you convert to an Archfey warlock if you previously had another patron) and can be the patron of Archfey warlocks of warlock level less than or equal to your own and you can change your own selection of warlock spell/features other than patron at the end of each long rest;
• your ability scores are now capped at 30 rather than 20.