I have a 2D animation and some work done in the "video editing" tab. When I "render animation", the only thing that renders is the text and music that I have done in "video editing"; it does not include the animation that I've done. How can I render both tabs into one video?
In order to add a scene into the VSE with a scene strip, you'll have to make a new scene for the VSE contents, as shown in this gif(from this post: https://blender.stackexchange.com/a/184931/37272):
To render from the VSE you'll need to check this box: