I need Pages for Os 10.13.6

If you have never installed Pages from the Mac App Store since Oct 2013, then it is not available to you for High Sierra.

If you have installed Pages v5 or later, then launch the Mac App Store on macOS 10.13.6 and sign in with the identical Apple ID that you used previously. Then holding the option key, press the Purchases toolbar item. A panel should appear showing the purchases for that Apple ID and if Pages is there, it should have an adjacent install/update button. That will produce a panel stating that it will be installing the last compatible version (v8.1) of Pages for High Sierra.

The only way to get Pages v8.1 for High Sierra is via the Mac App Store as I described. Otherwise, you might consider using Pages for iCloud, or on a current iPhone or iPad.

You sign into icloud dot com with your Apple ID and password. Pages for iCloud is among the applications there. I provided you a link to its user guide.

What browser are you using and on what operating system? This is not what you should see when you sign into iCloud and launch the Pages application.

The version of Safari on High Sierra may be too old now. Try FireFox 112.0.1, the current version of Chrome, or even the Brave Browser.