im using blender for rendering and photoshop for editing but i cant really find any background for this render and dont know how to blend a background with the subject in photoshop all i need is help to find and blend a background for this render if you can teach me how to blend a background that would be great too Render
Find a background image on a stock image website. There many of these online, such as Adobe Stock, Dreamstime, iStock etc. Do a search for "fantasy" illustrations. Alternatively just paint your own fantasy background image. In the example below I just chose a random fantasy type image for the sake of showing an example.
As far as blending is concerned, the following should work:
Paste your background on a new image layer, and drag it under your render layer.
Select the render layer in the layers panel, then select the white area in the image using the Magic Wand tool
Invert the selection
Add a layer mask
Artists generally try to make their images interesting to get attention. That reduces your options because you need a non-offensive background which must not steal the main object role. But in Photoshop it's quite easy to flatten images to fit your purposes. You only must tinker a little more than to make a hole to the white area and insert an image to the background. That's because the background should have compatible light conditions, colors, contrast, sharpness, level of details and it must plausibly continue the scene of your image further.
Your options increase substantially if you can accept also recoloring of your own image and inserting some foreground elements which bridge the background and the foreground.
To match light conditions and colors you generally need some adjustment layers to be able to search the right combination non-destructively. Layer masks in the adjustment layers and grouping are very useful to focus the effect to a limited area.
The next is an example to have something else than a desert scene which is already used in another answer.