Steps to deactivate your  Reddit account:

• Go to your Reddit settings page to remove your account.
• You can discover it by selecting 'User Settings' from your name in the upper corner of the Reddit website.
• Click the red 'Deactivate Account' link at the bottom of the page.
• Reddit will ask you for feedback on why you're deleting your account. To proceed, enter the password, then select 'You realise that deactivated accounts really aren't recoverable' and 'Deactivate.'
• Reddit will ask you a last time for confirmation. If you're sure you want to go ahead with it, click 'Deactivate.'

Read More: How do I delete someone’s Reddit account?