My photos are being save in pp3 format after saving them in raw therapee

No, they aren't. PP3 does not save photographs, it saves processing instructions. They are only for use within Rawtherapee so that it can reprocess the image in the same manner it did last time. Use C-s to save in some actual photo format like JPEG.

The PP3 files are not actual image files but "processing profiles". When I was using RawTherapee one year ago when I got started in photography, I figured out that the .pp3 files are rather files that contain the information of your edits in RawTherapee for each imported photo.

Technically, they are called sidecar files, and they are like the .xmp files that other applications like Lightroom and Bridge use for the same purpose. See: https://rawpedia.rawtherapee.com/Sidecar_Files_-_Processing_Profiles

You can't disable the creation of these files - they are needed to store your edits.

If you find them annoying, you can either hide them from view in Windows Explorer or tell RawTherapee to put them in a central cache. See: https://rawpedia.rawtherapee.com/Sidecar_Files_-_Processing_Profiles#Storage

To export images, switch to the export tab of RawTherapee and select your desired image format (such as png or jpeg)

You need to look at the bottom left of the photo editor and click the disk you see there. If you click the disk at the top right it is only saving the PP3 file. The bottom left saves both. I'm just learning the ropes too and have found the Rawpedia section of their website very helpful, you may too. Good luck!