To Access Secure Data Send Settings go to: Portal Settings -> Secure Data Settings. These settings can be configured for your technicians and locked down as well. 

Single - This makes the link a single use link. 

Save Logs to Ticket/Contact - This will save the actions of the tech and the user regarding the link. When the tech sent it, when the user opened it. 

Save logs to internal note - This will save logs of all actions to the internal note on your PSA instead of public discussion note section. 

Save data to internal note - Whatever password or text is sent to the user would be logged as an internal note. 

Lock user input - This allows you to lock the settings above so your users cannot change them. 

SMS Template - Messaging that is sent with the SMS link to the user. You can put text before and/or after the link. Do note remove the ${link} as this will break the functionality. 

Email Template - Same as above, you can add text before and/or after the link. 

Page Header Text - This is the header displayed to the user above the link when they receive the message and click the link. 

Message on Reveal Secure Data - This is a message is revealed once the user shows the data from the link. 

Click on Portal Settings -> Settings. Then Select upload new Image.