<apex:page standardController="O1">
    <apex:PageBlock>
        <apex:PageBlockSection>
            <apex:form>
                <apex:inputField value="{!O1.Email}" />
                ... etc
                <apex:commandButton value="Save" action="{!save}" />
            </apex:form>
        </apex:PageBlockSection>
    </apex:PageBlock>
</apex:Page>