Open Git Bash. Change to the root directory of Git Bash.

<pre lang="bash">
cd ~
echo $PATH
/bin:/c/Program Files (x86)/Google/Cloud SDK/google-cloud-sdk/bin

Edit .bash_profile or .bashrc. It was .bash_profile in my case. Showing a truncated path.

Add your custom path to the PATH variable. Save file. Exit Git Bash.

<pre lang="bash">
PATH="/bin:/c/Program Files (x86)/Google/Cloud SDK/google-cloud-sdk/bin:/c/custom/path"

Open Git Bash again and check your updated Path.

<pre lang="bash">
echo $PATH

Result.

<pre lang="bash">
/bin:/c/Program Files (x86)/Google/Cloud SDK/google-cloud-sdk/bin:/c/custom/path