How do I make a bootable USB?

I have personally dealt with the nightmare of a system failing to boot more than a few times—and let me tell you, losing critical files is a heartbreak I wouldn't wish on anyone.
After some digging, I stumbled upon some YouTube tutorials explaining how to put Ubuntu onto a bootable USB drive.
So, I went ahead and made one; it works perfectly fine so far, but I have a specific question—while I am in the middle of creating this bootable drive, is there any way to bundle my own portable applications alongside the default setup?
Alternatively, perhaps there is an entirely different piece of software designed specifically to handle this kind of customization.
Does anyone here happen to know the proper way to pull this off?

It doesn't quite work like that... you actually have to integrate those changes directly into the Ubuntu ISO file itself. You'll probably need to do a bit of Googling since I can't explain the technical specifics perfectly—I haven't done this exact process in a few years. The last time I tackled something similar was back when I had to slip specific chipset drivers into a Windows XP installation image just to get it running on a Lenovo laptop.

Could someone please point me in the right direction regarding what I should actually type into Google? I am having a bit of a struggle finding the specific terminology needed to pull up the right results—it feels like I’m searching for a needle in a haystack without even knowing what the needle looks like.

restlessdrifter12 said:Can someone tell me what to search on Google? I can't seem to find the right term to look up.

It's called slipstreaming.