Ellipses (...)

Use an ellipsis in ghost text to indicate that users can take action. Unless the ghost text ends with a question mark, end with an ellipsis.
For loading animations, use a one-word, visible label that expresses the operation in progress, in the user's language. End with an ellipsis. For example: Saving...
Refer to user interface elements using the element's exact label (including any end punctuation, such as an ellipsis). For example: Click Add... to browse for files on your local computer.
In a quoted passage, use an ellipsis to indicate any omission of text.

Salesforce Style Guide for Documentation and User Interface Text