From the Contacts Page in the Email Marketing Module, you can add recipients to the database by importing them from an .XLS, .XLSX. .CSV or .ODS file. Click on + LIST and then from file on computer to upload a list.

To type in a single new recipient, select the desired email list, then click on +RECIPIENT the click on type in a new recipient to open the dialog box to type in the name and email.  Click Update to save. If the constituent is not already in the database, a new constituent record will be created. 

Constituents can also be added to an email list from their profile page. Click in the white box under Email Lists and click on the list to add that constituent to the list.