Export frames of animation separately

Set each frame duration to 1 second. Then go to File > Export > Video render

Select "Images sequence", "All images" and set the frequency to 1 image per second.

Click on Render, and each frame should be exported to an image.

For people looking for exports with a transparent background..

First export all frames to layers:

Timeline panel > Flatten Frames Into Layers

Then Export all layers to files:

File > Export > Layers to files