Yes, Wordle is brilliant.
I'm guessing you wanted to make the background transparent while you
were in Wordle. Sadly,you must make the Wordle with an opaque
background. Once you are happy with it, make the screen shot. Then
allow Photoshop to do it's magic.
I use Paint.net. In Paint.net, I select the "tolerance" and the
"flood" mode to be "global", then, using the magic wand tool, click on
the background and delete it. et viola, transparent background. Just
save that as the type of file you wish. I use Paint.net because it is
free. I know you can do the same thing using Adobe's Photoshop. The
"global" allows Paint.net to include the background inside of letters
like "o", "d", "e", "a" etc.
I hope this was clear and helpful.
k