Follow the set of instructions given below to download the HP Smart App :
Check whether your smartphone is sharing the same wireless network as your printer.
Place your router and the smartphone closer.
Now, open the Play Store and download the HP Smart App.
Install the App now and open it to allow all the App permissions to proceed.
Now, click on the plus symbol found on the App screen to add your printer.
After connecting your 123.hp.com/setup printer with the HP Smart App, you can continue taking exclusive prints, copies, and scans at ease using the HP Smart App.
Download the HP Smart app from 123.hp.com (Android, Apple iOS, iPadOS), HP Smart - Microsoft Store (Windows), or HP Smart - Mac App Store. ...
If you are setting up HP Smart for the first time, you must create or sign in to an HP account to access all printer functions.
This may help, Jimmy