How to create message filter on Webmail (Roundcube) 1. Open your webmail. Click the settings icon then select Folders. Click the add folder (+) then input the folder name in the text box and save. 2. The folder that you created will appear here. 3. Click on the username/email address and select Email Filters. 4. Click the Create a New Filter button. 5. Assign a Filter name then choose a parameter base on how do you want your messages to be filter then click the Create button.