This process is as straightforward as it can be. Ubuntu 18.04 and 20.04 are the only "officially supported" platforms, in that they're the only platforms we do automated testing on.
$ apt-get update
$ apt-get install python3 python3-pip python3-dev git libssl-dev libffi-dev build-essential
$ python3 -m pip install --upgrade pip
$ python3 -m pip install --upgrade pwntools
Everything should be A-OK if the following command succeeds:
$ python -c 'from pwn import *'
If you want to assemble or disassemble code for foreign architectures, you need an appropriate binutils
installation. For Ubuntu and Mac OS X users, the installation instructions are available on docs.pwntools.com.
$ apt-get install binutils-*