This is how to apply gradients to multiple objects in Adobe Illustrator.
A lot of the times we want several objects that are on art board to actually have the same gradient. Now, a lot of the times people will create a gradient and people will want to create the gradient but they'll usually do them individually. If you want them to have the same gradient, there are two ways you can do this.
The first way is you select your objects. If we were to go all the way to the gradient panel we click linear, they'll all have that same gradient. Any new objects that you drag out are going to have the same gradient.
Now, if we want it to be a uniform gradient, which means that the far left object to the far right object all use the one gradient instead of it being each individual has a gradient from its left point to its right point, you select the objects. Go to your gradient tool and as you see on the window it will actually pop up and show that each one has their separate gradient.
To make them all one gradient, you click, after you've selected your gradient tool, and you drag that over to the distance you want from left to right for your objects. Then it appears as one smooth gradient from left to right.
That's how you apply the same gradient to multiple shapes in Adobe Illustrator.