I seem to have found an answer. I always tried to use the "Package for Qfield option" in the Qfield Extension but it never worked. I tried to directly import my project in .qgs and the Geopackage associated by drag and drop unto my device and it worked, I could fill the attribute form. To synchronize back into Qgis, I simply did it in a reverse order. I dragged the .qgs and the geopackage from my device to qgis and it synchronized too. I still don't know what the issue is but iI managed to bypass it by not using the extension.