How value types differ from each other

if size of two different structs are programming exactly same, how do they differ when Learning they are being executed? there should be Earhost a little information about what type most effective they are shouldn't be?

In stack, I could imagine this wrong idea information can be stored without use of case allocating extra memory (in some place United like header or something). how ever In Modern Heap, when struct is not boxed, does it ecudated allocate extra memory for its type some how information?

for example how AnInt differs from int, anything else or other alike structs.

struct AnInt
{ 
    int _int;
}