How do you do this rainbow text?

[Zac25383936x9dz]

I've been wondering for a long time and have been trying many different way of doing it but I cant seem to get it right. Any help is appreciated 👍

 

[Warren Heaton]

Import the multicolor image.  Add it to a Composition.  Create a Text Layer.  Set the Text Layer as the Track Matte for the multicolor image.

If you're up to speed on how to set multiple color stops for a Gradient Overlay Layer Style, you could do it entirely within an After Effects project; however, I found it better to pre-Compose the Gradient Overlay Layer to better control how the Gradient Overlay fill the Matte Layer.

Multiple color stops set for a Gradient Overlay Layer Style applied to a Solid.Pre-Comp set as Fill Layer and Text layer set as Track Matte.