Web to Lead Customization (please help)

hello i need you help on Web to Lead Customization

1) how do i take down Last name on fields , its defined as default and when you try to delete from fields that you want to be shown it wont let you take it down
2) how can i change the "save" button that is shown on site (site which i put the web to lead code) to "send"

please help

thx alot from ahead