In order to use Marketing in Salestrekker you need to configure Marketing and Connect details in Settings.
Editing Marketing details
In order to send email campaigns you have to first add Sender E-mail address. Go to Settings > Marketing and type in necessary information. Besides that you can add Reply-To and Blind Carbon Copy (BCC) address. In Email footer field you can enter contact details of your message and it will appear as signature in marketing email.
Editing Connect details
To use SMS marketing you need to open Settings > Connect and enable SMS usage. There you can also add sender ID by typing into "SMS From" field.