Hi @alokkumar121,

thank you for your comment. I'm the creator of @steemfinex.

to answer your question, it's so simple,

If you transfer STEEM to @steemfinex, you'll get STEEMP in your Steem-engine wallet.
If you transfer STEEMP to @steemfinex, you'll get STEEM in your Steem wallet.

So after exchange, any internal transfer is free of charge as you know.

maybe just trying it with a small amount gives you an idea (minimum is 1 STEEM/STEEMP, lower than that is donated to prevent spam)