Hello Abdul
If you create some packet tracer lab topologies for specific lessons, you can feel free to upload them as an attachment to a post. You can do this by saving your topology in a .pkt file and dragging and dropping the file into your post.
Concerning which emulator to use, I have personally used GNS3 as well as Cisco CML. Both are good for most topologies, for both routing and switching. I haven’t personally used EveNG, however, from what I know it too is more than sufficient for most certification needs.
Concerning administrative and operational modes, take a look at this post:
I hope this has been helpful!
Laz