Your hosting accounts can be removed using the account's hPanel with just a few clicks, however, please note, that your Hostinger profile cannot be fully removed for security reasons.
Access the hPanel of the account you wish to remove, scroll down to the Other section and search for the Deactivate Account menu.
IMPORTANT: Note that when you deactivate your account, you can still restore it with all of your data until the account's expiration date and 21 more days after it. However, if you press Delete, all of the account's files and settings will be fully removed from the server. In such case, make sure to make backups of the account you wish to remove to avoid any loss of files and previous hard work.