Update (WSL2)

WSL2 runs in a real virtual machine using a real Linux kernel, so it's actually possible to do anything a Linux VM can do, including running 32-bit code. Just install 32-bit libs by running

sudo dpkg --add-architecture i386
sudo apt-get update

But again, you should really opt for the 64-bit version, especially if you have the source code. 32-bit Linux is much less maintained than the 64-bit version, since there are far fewer 32-bit only hardware in the last decade along with a significantly less number of users and testers. One example is that the Meltdown/Spectre patch for 32-bit Linux came out more than half a year later than the 64-bit version, and it's still buggy for years later

Original Answer

You simply can't do that. WSL doesn't support 32-bit apps!

Most (if not all) Intel and AMD CPUs in the last decade support the x86_64 instruction set and there's no reason for Microsoft to spend time and money on supporting a 32-bit version of Linux. Most developers and Ubuntu users are running the 64-bit version anyway

No, we don’t support x86 32-bit at this time: We currently depend on x64-only instructions and mechanisms to ensure fast & stable performance.

Bash on Ubuntu on Windows

• Support for 32-bit i386 ELF binaries
• Please enable WSL to run 32 bit ELF binaries
• Exec format error 32-bit executable Windows Subsystem for Linux?
• Windows Subsystem for Linux Overview: We recently announced Bash on Ubuntu on Windows which enables native Linux ELF64 binaries to run on Windows via the Windows Subsystem for Linux (WSL)

In addition to the answer for wsl 2, I also had to install sudo apt-get install gcc-multilib so libc6 have been installed and ELF 32bit can be executed