How to modify a slice element which is a struct in golang?

Try

s[0].value = 5

This gets to the backing store of the slice. Also

p := &s[1]
p.value = 6

You can also take the address of the slice element directly and de-reference it:

func main() {

    s := []Type{{0}, {0}}

    // Prints  [{0} {0}]
    fmt.Println(s)

    // De-reference the address of the slice element
    (&s[0]).value = 5

    // Prints [{5} {0}]
    fmt.Println(s)
}