How do I reinstall Ubuntu Software in Ubuntu 20.04 LTS version?

Install

You can install Ubuntu Software like so:

sudo apt install ubuntu-software

or install Gnome Software in newer releases of Ubuntu like so:

sudo apt install gnome-software

You can reinstall Ubuntu Software like so:

sudo apt install --reinstall ubuntu-software

or reinstall Gnome Software in newer releases of Ubuntu like so:

sudo apt install --reinstall gnome-software

You can reset Ubuntu Software to its vanilla settings.

First, purge it like so:

sudo apt purge ubuntu-software

Then, install it like so:

sudo apt install ubuntu-software

or reset Gnome Software in newer releases of Ubuntu.

First, purge it like so:

sudo apt purge gnome-software

Then, install it like so:

sudo apt install gnome-software

You can remove Snap Store that might be already installed ( although I recommend you leave it ) like so:

sudo snap remove snap-store

and you can install Snap Store again like so:

sudo snap install snap-store

I heard they switched to snap store. You may try either of the two.

sudo apt-get update
sudo apt-get install gnome-software

sudo apt-get update
sudo snap install snap-store

You can try looking at the snap store website and downloading the store from there snap store