import text

It's not entirely clear what you want to do.  If @Andrei_D has not answered your question, you can copy and paste text from any text editor to a text tool layer.

If I got it right, you want to import some "live" content from an external text file.

I believe, this can be only achieved with the data-driven graphics approach.

In PSE, you may need Elements+ to access this feature.

Importing data from an external text file is explained here:

https://elementsplus.net/help/en/import-data-set.htm