Export Animations in After Effects
1. When you are ready to export go to File> Add to Render Queue
2. Click on the little triangle next to "Output Module" as shown below and choose H.264 as your export format.
3. Click on the Yellow Name of your File next to "Output To" as shown below and choose where you want your file to go. You can also adjust or change the name of your file here. The file format should read H.264 (*.mp4). Thenk Click Save.
4. Click on the Render button as shown below and wait for your file to render. When you hear the Chime your file will be done.