You can remove the optical drive and install a HDD caddy in its place, so you have the SSD and the HDD installed at the same time. Then buy an external USB optical drive if ever you need that. If you use the optical drive a lot then that might not be an option for you, but most people hardly ever use the optical drive anymore these days.
Can i have 2 drives in my laptop? Like one SATA and one m.2?
Is it possible to add SSD In addtion to HDD..? or HDD has to be removed to add the SSD?
You can remove the optical drive and install a HDD caddy in its place, so you have the SSD and the HDD installed at the same time. Then buy an external USB optical drive if ever you need that. If you use the optical drive a lot then that might not be an option for you, but most people hardly ever use the optical drive anymore these days.