Hey @niamhy642 thanks for posting!
So Presale codes are provided to "top fans" of an artist. Now what defines a top fan is not necessarily clearly defined from what I can find.
However there are some other things you have to make certain of to even be able to recieve these presale emails:
- Make sure you have opted into Artist Updates emails on your account page.
- Make sure your email is correct under your profile.
More information can be found under Spotify's official article regarding Fans First emails, this post from Meredith, and this comment from Meredith.