I wouldn't recommend hard coding credentails into a script, best to obfuscate the string using something like below.
https://github.com/brysontyrrell/EncryptedStrings
As far as making the script be a clickable executable. Automator or shortcuts may work for this; depending on the target version of macOS. The most straightforward way would be t o append dot command to the shell script, this would cause it to run when double clicked if permissions are set correctly. ie local admin.command
