tnx 4 the replay Chambone, i did as u said but something not working

when i check the file in web browser it does has the transparent effect,
but when i check it in different picture viewer software i get a white image
and if i place it in my iPhone it gives me a black background, what am i doing wrong ?
P.S. i attached the file i made and a screen shot of what i get on my phone:
View attachment 340616
View attachment 340617