how can we use http instend of https??
HTTP means HyperText Transfer Protocol, and HTTPS means HyperText Transfer Protocol Secure.
It is however just a secure layer over the transfer protocol.
It requires a SSL certificate, which in some cases costs money and in others are free, depending on your needs.
If you just need it in order to just have some kind of certificate, I could recommend using Cloudflare's free membership, that can be setup to use their SSL certificate, and then you can have HTTPS instead of HTTP for free without doing much.
However if you prefer having your own you need to setup the certificate yourself, I however recommend using Forge for this since it makes it so much easier.
There you can even enter your own certificate that you bought or signup for a free one by Let's Encrypt.