Configure Oh-my-zsh on Git Bash (Windows)

Step 1. Download the latest MSYS2 zsh package

… from the link (https://packages.msys2.org/package/zsh?repo=msys&variant=x86_64).

The filename should look similar to zsh-5.9-2-x86_64.pkg.tar.zst.

Step 2. Extract and merge

Extract the archive and copy the contents (including the /etc and /usr folders) into C:\Program Files\Git. Merge the folders.

Step 3. Open Git Bash and start zsh

Open Git Bash and Execute zsh. Configure as prompted.

autoload -U zsh-newuser-install
zsh-newuser-install -f

• To configure the history, enter 1, change the values if you like by 1-3, and then enter 0.

• To configure the completion, enter 2 to “Use the new completion system”, and then enter 0.

• Enter 0 to save the settings.

Step 4. Setting zsh as the default shell

… by appending the following into ~/.bashrc:

if [ -t 1 ]; then
  exec zsh
fi

For further configuration and beautify, consider Ubuntu Configs

Reference: link