As I interpreted the question, you seem to be asking if you want to make your own coin then would you require to use some part of the code Bitcoin uses? The answer would be that it depends on a lot of factors and isn't as simple.

• Is your coin a fork of bitcoin? If the answer is yes then you might be developing a coin that you could call a "fork" which would heavily rely on the existing code but most future development might depend on the choice of the community and the developers of said forked coin
• Are you just developing a smart contract based coin? If yes then you're more or less leveraging the existing blockchain for the coin using which you make the smart contract then yes you will be pretty much restricted to suit the coin which is acting like the "parent" for example a common coin that's used to make tokens would be Ethereum