Autocomplete is not working for include & require PhpStorm

It should do this by default.

Place the cursor in between the '' symbols and hit ctrl+space to check available options.

If that's not working for you - please record a screencast or a set of screenshots that would show the issue & what values you're expecting to be shown.

I have tried your ctrl+space too. But suggestions for include & require variables not working.

Vscode have this feature. How can i add this setting to my PhpStorm?

Press ctrl+space twice:

For this kind of projects you can also enable "Search for variable's definition outside the current file" checkbox at Settings (Preferences on macOS) | Editor | Inspections > PHP | Undefined symbols | Undefined variable.

Can you export your ide setting, please? I guess if I import your ide setting it might work.

I'm using default settings. You can get this by using File > Manage IDE Settings > Restore Default Settings.

Did you try pressing ctrl+space twice?

ok pressing ctrl+space twice is working. I can now see the code completion but can I get this code completion without pressing ctrl+space twice?

"Quick" code completion in global scope was disabled intentionally: https://youtrack.jetbrains.com/issue/WI-912 because of performance problems in large projects with hundreds or thousands of globally defined variables.

You can type $ and then hit ctrl+space once to list available variables.