apex:page
This tag represents a single visualforce page. Any visualforce page should be wrapped inside a single page component tag.
<apex:page>
//Your visualforce page content.
</apex:page>
Eample:
<apex:page>
<H1>Welcome to Salesforce tutorial<H1>
<p>This tutorial is useful for to understand Salesforce basics</p>
</apex:page>
apex:page attributes:
Action, apiversion, applyBodyTag, applyHtmlTag, cache, contentType, controller, deferLastCommandUntiReady, doctype, expires, extensions, id, label, language, lightningStylesheets, manifest, name, pageStyle, readOnly, recordSetName, recordSetVar, renderAs, rendered, setup, showChat, showHeader, showQuickActionVfHeader, sidebar, standardController, standardStylesheets, tabStyle, title, wizard.
Refer this for more details:https://developer.salesforce.com/docs/atlas.en-us.pages.meta/pages/pages_compref_page.htm