Hi @mpaon, welcome to our community!
Great question. I’m wondering if you’ve had a chance to check out this amazing announcement posted by my colleague @AlexSavchuk: Uploading a file to monday.com with variables - example in NodeJS.
In it, he outlines how to upload a file with variables. With regards to an example using PHP, feel free to check out these threads I found:
Let us know if you have any other questions at this time!