When you create an FL Studio project which uses a third party samples, it’s best to export it to a Zipped loop package, so finally, all your samples and the project file will be archived in a Zip file.
When you export it to a “Zipped loop package”, FL Studio will automatically export all the samples with it.
This is a very handy feature to keep your FL projects and samples in safe as it may happen that you accidentally delete the folder where your samples originally reside or your hard drive may crash, etc.
Also, if you want to share your FL Studio project files with other FL Studio users and you’re using third party samples, they can’t open it properly if they don’t have exactly the samples as you’re using.
But you can solve this problem by exporting your project to .zip.