Interfolio provides free, specialized accounts for letter writers so that there are no barriers to uploading letters into your account.  However, these accounts are specifically limited to only being able to write letters or upload letters on behalf of applicants.  In order to request, manage, and send out letters of recommendation or other non-confidential documents of your choosing, you will need to upgrade your account to a Dossier.  To do this, simply log into your account, click the tab at the top of the home page that says "Upgrade to Manage Your Credentials," and follow the steps to upgrade your account to a Dossier.