Suppression à color to make it transparent

I need to supress a color and make it transparent. I don’t find a tuto to do it. Could someone help me ?
Thank you very much !

Hi there @Emmabrunelle,

Here’s a quick demo showing how to adjust Opacity:

If this doesn’t answer your question, just let me know and we’ll sort it out!


Thank you Helen. it’s not what I’m looking for. I import a picture with a white background. I want to suppress the white and remplace it by transparency.