First you will need to expose the HTML ID attribute. To do this first go to your Bubble App, then go to Settings -> General and under General Appereance look for 'Expose the option to add an ID attribute to HTML elements' and check it.
Then you will see there's an input at the bottom of any element in your Bubble Editor.

You need to give the element an ID (e.g element_id_1). Then in the Workflow create a new Action and search under the Plugin Tab  > Animate .

Place the ID you gave to your element (e.g element_id_1), then select your desired animation and that's it!
You can also set if you want the animation to happen on hover or click.

For a full list of the animation names please visit demo page