A third-party user input content item is presented on a user device of a user. Third-party authorization for the third-party user input content item to be combined with other content items is determined. Responsive to determining the third-party authorization, a combination graphical element is automatically presented on the user device. The combination graphical element is user-selectable to invoke a combination function. Responsive to determining a user selection of the combination graphical element, the combination function is invoked, enabling the user to combine the third-party user input content item with another content item to create a combined user input content item.