How do I export whole Unity project with all scenes?
You can zip the Assets folder and ProjectSettings folder and ignore all other files and directories.
You don't need Library and Obj folder. The get created automatically.
The project files (.csproj) and similar files also get created automatically.
Alternatively you can export the whole project as a package:
Use Export Package to create your own Custom Package.
Open the project you want to export assets from.
Choose Assets > Export Package… from the menu to bring up the Exporting Package dialog box.
In the dialog box, select the assets you want to include in the package by clicking on the boxes so they are checked.
Leave the include dependencies box checked to auto-select any assets used by the ones you have selected.
Click on Export to bring up File Explorer (Windows) or Finder (Mac) and choose where you want to store your package file. Name and save the package anywhere you like.