Installation

Adobe now offers the current and ONE older version via the online program manager
Go here for all older links https://prodesigntools.com/adobe-direct-download-links.html
-Prodesigntools is an official Adobe partner, and the links go to Adobe, not a 3rd party site
.
Computer crashes happen... the FIRST time you download a program make an external copy
IF/When you do have a download, be sure to copy it to AT LEAST one external device
-you should ALWAYS keep a copy (or two!) on an external device
-since Adobe DOES SOMETIMES REMOVE OLD VERSIONS FROM THE SERVER
-a usb flash drive or external hard drive, or write to a CD or DVD
-plus a text file containing your serial number if you have a serial number program

to follow @Manan Joshi's suggestions:

to check your account and to verify your subscription is what you expect and to verify your adobe id, https://accounts.adobe.com

to install the cc desktop app, start here https://creativecloud.adobe.com/apps/all/desktop?action=install&source=apps&productId=creative-cloud and use it to install your adobe subscription and trial programs after signing-in using the same adobe id used to confirm your subscription.

if you have trouble downloading, use the alternative download site at page bottom here, https://helpx.adobe.com/in/download-install/kb/creative-cloud-desktop-app-download.html

This is not how it works, if you have a valid subscription then you can use any version of CC software although only the latest two versions are supported by Adobe. So the questions for you are

• What plan do you have exactly? Can you see the plan in your accounts section on the Adobe site?
• From where did you download the CC2018 version of the software?

-Manan