Can I use Adobe Acrobat as Portable in USB?

++ A caveat to Try67 correct answer and Nancy O'shea spot-on observation

No you are not able to run an  application to run straight of  a flash USB device because it depends on an operating system to interfacte with it.

Some executable programs (.exe)  that are very small in size can run from any folder (or USB device) without installation required.

Adobe Acrobat Reader is not that kind program BUT you can , however, install Windows 10 to a flash USB device making the USB bootable with the MS Windows 10 operating system .

Pretty much, this is  true with different operating systems.

I've been doing this for years, and even installing a bootable version of a linux distribution in very old 1.2GB Apple MP3 player sticks; people used to throw away those because they were succeeded by better MP3 players back in the early year 2000. 

This is also possible with cell phones, as you can adual-boot in an unlocked and rooted Android device, for example, and be able to use the cellphone  as a flahable USB device with other operating systems in it.  

NOTE: Before someone raises the flag in these forums about this guidance , this is exactly what Raspberry Pi is all about.

As a computer repair technician I can attest that this is also how you're able to repair corrupted hard drives when you can't boot from them anymore,  retrieve lost passwords, fix hard drive partitions, inspect for viruses and malware,  perform forensic analysis, do backups and transfer data to other external devices, analyze and view files without executing malicious code directly in the victimized computer, testing operating systems for behaviors on specific hardware,  and much more when it breaks down to networking!

In other words, there  is nothing illegal or inappropriate about this guidance.

You just need to confirm in your organization that if USB devices are not allowed to be plugged in on any computer, then don't do it. 

For the obvious reasons that I explained above, I've worked in places where you're not allowed to plug a phone to a computer to charge its battery. 

If that is the policy you have to follow those poilicies.

Again, it is very important that you ask and confirm that you're indeed allowed to plug a USB device to any computer in that school, specially if the policies are set to not allow installing software on them. 

But if that organization is OK with it, then consider the following:

• the BIOS need to be enabled to select alternate boot methods  in the  computer(s) that you will use the USB 
• Also, in the case of windows 10 you need to consider a flashable USB 3.0 device with at least 32GB of storage capacity and fast writable speeds of 300Mb writes per second or better (preferably 400Mb writes per second). Esle MS Windows 10 will hog the speed of its own operating system and any app that you try to run directly from the USB device itself.
• The USB device is basically acting as a bootable hard drive partition, so in this case, Yes you can run Acrobat or Reader like this. It is important that you know enough about hardware requirements beforehand and check that those computers meet fast enough processing and RAM speeds to support this method
• Using this method You are be able to install USB applications like Adobe Acrobat Reader in a USB, but you will always need the operating system to boot from, and a computer where you can boot it from, and run it from. 

Thanks for your answers, I search over the Google and found an helpful download link of acrobat reader. Are you recommending me to dowload it from unofficial site (https://filesmint.com/adobe-reader/) or I should use official link and than install it on all of computer library computers?

Cheers

Chris