How to apply Transparent Gradient?

Greetings good people,

How to apply a transparent gradient on a sprite/shape painter object like this?

gradientTransparency

Any help would be very appreciated. Thanks!

I am not sure you can go with transparent gradient using shape painter
However for image i did this in GIMP
You can do the same in a lot of image editors
And A LOT of tutorials how to do so on youtube
Gradient

Some more streamlined versions below

Gradient2
Gradient3

Another option is to use a sprite and use the sprite masking extension.