@harsh_rajput You should be able to install FDK v7.4.2 using this command:
npm install https://dl.freshdev.io/cli/fdk-7.4.2.tgz -g
You will have to run this on Node.js v12.x.
Please note that FDK v7.x is scheduled to be deprecated on August 31, 2022, and the v7.x branch will not receive any further feature updates. So, we still recommend that you update to FDK v8 and migrate your apps by then.
(Edit: Updated URL)