I can't help you with the language aspects of it, but for food contact packaging in the EU the general reference for compliance is Regulation (EC) 1935/2004 relating to food contact materials. If the material includes plastic then we would also expect to see confirmation of compliance with Regulation (EU) 10/2011, including reference to the applicable overall migration limits (OMLs) and simulants for the packaging and the foods with which it is intended to be used.
Similarly we expect to see compliance with Regulation (EC) 2023/2006, relating to good manufacturing practice for food-contact materials.
As you're dealing with plastic (I think?) you may also consider including confirmation on specific migration limits (SMLs), potentially as a list of materials used that are subject to these.
Customers may also have specific requirements that they want/expect to see - for example this could be around the absence of aromatic amines, heavy metals (Directive 94/62/EC), phthalate, PVC, Bisphenol A, genetically modified organisms, allergens (Regulation (EU) 1169/2011), BSE/TSE, epoxy derivatives (BADGE, BFDGE, NOGE) etc