I have a macbook Feb 2008 can I upgrade to OS X el captain
No, you cannot. The system requirements are below.
MacBook (Early 2015)
MacBook (Late 2008 Aluminum, or Early 2009 or newer)
MacBook Pro (Mid/Late 2007 or newer)
MacBook Air (Late 2008 or newer)
Mac mini (Early 2009 or newer)
iMac (Mid 2007 or newer)
Mac Pro (Early 2008 or newer)
Xserve (Early 2009)
I have a macbook Feb 2008 can I upgrade to OS X el captain
Welcome to iMore! Here are the system requirements for OS X El Capitan: https://support.apple.com/kb/SP728?locale=en_US
Unless you have a MacBook Pro from that generation it looks like you just missed the cutoff.