Open powerpoint and go to View tab. Then click on Slide Master. Choose the general layout template for all Slides or the individual layouts where you want to add the watermark image or text to. Here you can add a text or picture watermark. Text watermark are more suitable for cases where we need to show a CONFIDENTIAL slide text, or DRAFT text from one corner to the other, or if we are creating a TOP SECRET powerpoint template while picture watermarks in powerpoint are more useful when you want to embed an image with transparency in the background of every slide in the presentation.
If you insert a Picture, right click on the image to select Format Background options and make sure to set the Fill with transparency of about 20%. This way, you will make the background powerpoint image to look as a PPT watermark effect.
Now you can get back to the Normal View and start adding your presentation Slides in powerpoint with the watermark effect on the background. Alternatively you may want to read the article where we explained how to use a free background watermark for powerpoint 2010.
If you need free backgrounds for powerpoint presentations, don’t forget to check the free PPT templates and backgrounds from this website.