Use an In-line visualforce page

                                        Add In-Line Visualforce page.

1. Create Visualforce Page.

<apex:page standardController="Account" showHeader="false" >
  <center><h1 style="color:red">In-Line Visualforce Page</h1></center>
  <apex:pageMessage summary="Added In-Line Visualforce Page on Account Page Layout." severity="Info" strength="3" />
  <apex:form >
  <apex:pageBlock >
  <!-- <apex:pageblockButtons >
     <apex:commandButton value="Save" action="{!save}"/>
   </apex:pageblockButtons>-->
     <apex:pageblockSection title="In-Line Visualforce Page" columns="1">
       <apex:outputField value="{!account.name}"/>
       <apex:outputField value="{!account.phone}"/>
       <apex:outputField value="{!account.fax}"/>
       <apex:inlineEditSupport event="ondblClick" />
     </apex:pageblockSection>
  </apex:pageBlock>
  </apex:form>
</apex:page>

2. Go to Page Layout and select VF Page.

Output :