Is there I can change the front end of Chirpstack

I am working on project and I want to change the front end of web interface.

https://www.chirpstack.io/docs/chirpstack/contribute.html

You would need to change the frontend as part of a full build, but sure.

Can I do this if I have downloaded Chirpstack viva ubuntu packages(apt) edit those files and if so then how

Thanks

You can. E.g. you install ChirpStack and configure NGINX to serve the static files (all endpoints that do not start with /api prefix) from a different source.