select-all-strings ("sas")

See this command in the command table.

Home ribbon >> Select >> Select >> All >> All Strings (toggle).
Use the quick key combination "sas".
Using the command line, enter "select-all-strings".
On the Find Command screen, highlight select-all-strings and click Run.

Command Overview

Select all loaded string data. Selected data is highlighted.

Strings can be added to the already selected string data by holding down <CTRL> whilst selecting (click) with the mouse. Reselecting an already selected string using <CTRL> deselects the string.
The mouse can either be clicked to select a single string, or clicked and dragged to define a selection box. Whether strings will be selected by the defined box depends upon whether strings are set to be selected if all inside the box, or partly inside the box. This is controlled from the Data Selection area on the Points and Strings tab of the Project Settings dialog.

Command steps:

Note: Data will only be selected if the displayed 3D object overlay is enabled on the Overlay Selection screen.