You can delete your account by clicking the Edit Profile button on your Pexels profile page, if you do not have any photos approved for inclusion in Pexels search results. You will find an option for account deletion in that page.
If you have photos which have been featured in Pexels search, you will need to send an email to info@pexels.com with "Delete" in the subject line. We will then delete your account right away.
If possible, let us know why you're leaving—it always helps us to know so we can keep making Pexels better!