Does an sd card hold texts?

An SD card with photos on it actually contains quite a lot of text in the form of metadata, which describes the parameters of the camera at the time the photo was made. f-stop, ISO speed rating, exposure time and so on.

To this you may with appropriate software add titling and descriptive Words, and classifications to aid sorting.

Or you can use it just as a hard disk, on which to store as much text as you can write.