Dear Geeta,
For Fixer Uppers - you may need several different permits....depending on what all you undertake? From Planning, to Building - Electrical, Plumbing etc etc....if you extend, then foundation. It is a project, can be done but it is a process and time commitment you have to be financially, mentally and physically prepared for.
I live and work, and am also a Public Safety Commisioner with the City of Cupertino. I have done Contract work for the City and can explain the entire project outline to you. Construction is undertaken all over in Cupertino, and if you follow all the City Codes/Guidelines and work with permits as needed, there is no reason you cannot undertake a project! You meet their guidelines, you can get a permit.
DO check out my website, and get in touch with me for further information,
Be well and safe, regards,
Nina Daruwalla

The Cupertino planning department is very helpful and easy to work with. As long as you are requesting to do work within the scope of their planning guidelines, this should be an easy process for you. Make sure you check for any current city violations not just for remodeling/fixing up plans. Some current violations require immediate fixing or are subject to daily penalties.