Unable to add text to the back cover of a book jacket

I agree with @hatstead that Elements is not the ideal tool for adding paragraph text (if that is what you are trying to do).

I think the problem you have faced is that the text you are copy and pasting does not have line breaks recognized by Elements.  Hence, you are getting the single line of text that probably is stretching over the width of the page.  However, if you add line breaks into the text layer, you can get it to fit into the page without overlap:

In my example above, I copied a paragraph of text from a web page and pasted it into the text layer.  I then randomly added line breaks (with the [Enter} key).  This broke the layer down to a manageable level which can then be properly edited.

I also typed up some lines of text with line breaks in Word and was able to get a decent result pasting it into an Elements documents.

Hope this helps.

Photoshop Elements is not a text editor. I suggest that you enhance graphics and pictures in PSE and save them.

Then, open WORD (or similar), type your text with appropriate font & pt size, and insert the picture. In WORD you can resize the picture with the corner handles of the bounding box to suit. Since I had not done this for a while, I just tried it and it works well.

See this for a more sophisticated approach:

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