You can try editing it in paint or a more professional image editing program. Or you just use an image with a transparent background right away. The image must be .png, you may include that in your search. Online the transparent background is often represented by light gray and white squares as a background.

The best image edidtig app according to me is photoshop cc U can buy it officially or if u don't want then u can get its pirated version on chrome(it may contain virus) Download it on ur own risk