Ok, let's say I have an offline wallet for storing my bitcoin, now I have got a good amount of bitcoin, but i don't want to take out everything from the wallet, I only want to take out a small amount, is that possible?
Yes, bitcoin is divisible to the 0.00000001 bitcoin, we call this small amount the "Satoshi" for example so even if you got less than 1 bitcoin you have a pretty wide margin on what amount you want to transfer it could be 200.0099 or 0.0005123 be careful of the fees though
For the transfer part I suggest you to use electrum
You will find more useful information about the transfer from cold to online wallet there: Can I spend/transfer bitcoins directly from cold storage?
Yes, it is possible. Basically any bitcoin wallet application should allow you to choose exactly how much to send to another address.