Select the folder in which you want to save the Images to.
The standard Image format for VFX Image sequences is OpenEXR. The reason is, that this format supports 32 Bit depth and a lot of multiple channels which can be useful for compositing, but that’s another topic.
In Color, you should pick RGBA. That includes the Alpha Channel if you have transparent parts in your Image.
When it comes to color depth, you can choose between float (half) (16bit) or float (full) (32bit). The difference is 32bit Images contain more information which enables you, to do more in post-processing. The downside is, that the files are roughly 2 times bigger. For most of the project, 16bit will be more than enough.
As in every Image format there are also algorithms, to compress the Image and make it smaller while maintaining as much quality as possible, probably the best for CG is Pxr24 (lossy). Which was developed by Pixar specifically for CGI.