Sample configuration doesn't appear on Gear icon click

[dims12]

PHP version: Doesn't apply
XDebug version: Doesn't apply
Adapter version: Doesn't apply

Your launch.json: Any
XDebug php.ini config: Doesn't apply

XDebug logfile (from setting xdebug.remote_log in php.ini): Doesn't apply
Adapter logfile (from setting "log": true in launch.json): Doesn't apply

Code snippet to reproduce: Doesn't apply

It is said in documentation, that sample launch.json configurations will appear on clicking gear icon. But this doesn't happen.

[AnrDaemon]

Not specifically that way, but "Add configuration" dialog is missing PHP debugger.
You can only create template configuration if you don't have launch.json at all.

[zobo]

This was fixed a while back and should be in latest releases. It was also extended a lot in the last release (see #585 and #588)