Pages can’t be installed on “Macintosh HD” because OS X version 10.14 or later is required. I have a two mac books same version. I am now trying to install numbers,pages and keynote - I am getting this message. How can i Install these basic apps.

Believe what you are being told. You must have Mojave or later installed before you can download v10.1 of Pages, Numbers, and Keynote from the Mac App Store. If your MacBook Pro is a 2012 or later model then you can upgrade to Mojave (view in Safari) to satisfy the first sentence.

If you never had any of these Apple applications installed, then you are done until you upgrade to Mojave or later.

If you have had them installed, then you might be able to reinstall them via the Mac App Store and using the same Apple ID that was used to install them previously. Launch the Mac App Store, sign-in, and then press the option key while clicking the Purchases tab. If you have Pages, Numbers, and Keynote present with install or update buttons, then click to start the installation. This will inform you that it cannot install the current application versions from the Mac App Store, but may offer to install the latest versions for your version of OS X. Or it may not.