You can create an animation based on a set of keyframes - camera positions at particular times. QGIS 3D then interpolates the camera positions/rotations in between the keyframes.
To create the keyframes, first set the scene for your map, by rotating, zooming or moving the camera. Then assign a time to the frame. There are several methods for interpolations between keyframes.
This feature was funded by QGIS community through crowd-funding
This feature was developed by Martian Dobias (Lutra Consulting)