Did you hit F12? If not, hit F12.
Did you notice the arrow button? Push the arrow button. Put the starting point of the arrow somewhere on the picture. Hold the mouse button down and drag it to the destination. Let go of the mouse button. You have an arrow. You can adjust the color and width at the bottom of the drawing tools window.
Did you notice the text button in the drawing tools window? It looks like the letter "A". Push the A button. Click the mouse where you want the text to appear. A box should appear on the screen. Type something into the box, and hit OK. You should have text on your JPG.
Here's another way to do text:
thing got was this post.
Try YouTube. There are literally hundreds of tutorials on Irfanview (of radically varying quality). Also, Google for "Irfanview Tutorial" or "Irfanview Instructions". Plenty of those to be found. The reason your search didn't find anything for "text and arrows" is that these are two seperate topics and it's unlikely that you'll find both in a single document.