For a long time I used Type>Create Outlines to turn my text into objects, then applied a gradient fill. This is fine, but means that your text is no longer editable. I usually created a copy of the editable text before creating outlines and hid it in the layers panel, just in case I needed to edit it later down the line.
But there is a way to keep your text editable AND apply a gradient fill.
But wait a minute. That means that there are two fills, one on top of the other. If you look closely you may be able to see the original fill colour behind the new gradient fill. To remove the original solid fill:
Your text now only has a gradient fill, and is still fully editable.
Found this tutorial helpful? Find out how to apply a gradient across multiple objects.