What's the best tool for creating Ubuntu-based distro or for creating ISO Image from customized Ubuntu?

Question

I need a tool which allows me to create ISO Image from customized Ubuntu 20.04 LTS.

Answer 1

Use Cubic to customize your OS and generate an ISO image.

sudo apt-add-repository ppa:cubic-wizard/release
sudo apt install cubic

Cubic has a GUI "wizard" (to click through the steps). Since you mentioned you know how to customize your OS, you will just need to apply your customizations using the command line on Cubic's Terminal page.

Cubic handles all the hard stuff about packaging the files and creating an *.iso image, so it makes creating a custom ISO very easy. If you forget something, or need to make a change, its very easy to go open an existing project and make "tweaks" without having to re-do everything.

Also, take a look at How to use Cubic to create a custom Ubuntu live CD image? for more details.