This can be done with small text or large. It’s particularly useful for when text won’t show up clearly otherwise.
Open up a new image and colour it black or whatever you would like your outline colour to be.
Click , and then click your image and type in the text you want. Make sure you pick a different colour to the one you already chose.
Your text will have a floating dotted line around it, so now go to ‘Selections’ > ‘Modify’ > ‘Expand’, and choose either 1 or 2 pixels. Press ‘Ok’.
Right click your text and press copy, then paste as a new image. Your text should now have a border around it! It should look like this: