Before we dig deep on this subject, I assume we got a Laptop connected to the internet over wifi and we are running Ubuntu on it. Now connect the Raspberry Pi (running raspbian os) to the laptop using a LAN cable.
To share the internet connection open the Network Manager application and edit the Wired Connection.
Click on the IPv4 Settings tab and select the Method - Shared to Other computers.
Once the above steps are complete reconnect...
