If you think your code will make a valuable addition directly to Sage
(and others with knowledge of the relevant area agree) you could
certainly open a ticket to propose an enhancement. However, if you
just wrote some code using Sage but that does not need to modify any
of the Sage sources directly, you can always distribute your code as a
separate package that depends on Sage. E.g. by following
https://github.com/sagemath/sage-package
But it's not exactly clear what you need/want to do. Where is your code?