There are many tools out there to ensure that the background for images is transparent. This includes the pro (paid) version at https://www.canva.com, but it is also useful to have a free tool. Below are the steps for using the online tool LunaPic
Navigate to https://www8.lunapic.com/editor/
Click “Upload” in the upper left corner of the screen of the home page.
Once the image is uploaded, click “Transparent”.
The site will automatically select the background color to make it transparent.
Click “Apply”
If the site did not make the entire background transparent click on the part(s) that need to be adjusted and apply the changes each time another portion is adjusted.
Once satisfied with the background click “Save” below the image to download.