Something like that, than marshal to json

package main

import "fmt"

var StringsArray = []string{"Person1", "Person2", "Person3",
                            "Person4", "Person1", "Person2"}

type MyStruct struct {
    Name string
    Count int
}

func main() {
    mySlice := []MyStruct{}

    for i, name := range StringsArray {
        fmt.Println(name, i)
        mySlice = append(
            mySlice,
            MyStruct{
                Name: name,
                Count: i,
            })
        
    }
    fmt.Println(mySlice)
}

you can try it here - go playground

The short & direct answer: no, use the array index instead of the value

So the above code becomes:

package main

import "fmt"

type MyType struct {
    field string
}

func main() {
    var array [10]MyType

    for idx, _ := range array {
        array[idx].field = "foo"
    }

    for _, e := range array {
        fmt.Println(e.field)
        fmt.Println("--")
    }
}

Use the range keyword. https://github.com/golang/go/wiki/Range

for i, person := range *manager.allPerson {
    fmt.Println(person.name)
}

Note that the compiler will be angry if you don't use the index var i. If you don't intend to use it, replace with _.

To further explain, your original error was due to the fact that you correctly dereferenced your *[]Person the first time, but not inside the for loop.

fmt.Println(manager.allPersons[:ii].name) // wrong
fmt.Println((*manager.allPersons)[:ii].name) // right

Also, given that your slice contains Person struct values, it will have to copy it if you use the optional second value in the range expression. Thus, it would be more efficient to keep using just the indexes.

As a suggestion, don't use a *[]Person, use []*Person, which is probably what you intended to use anyway. A slice is already a pointer value. Using []*Person you don't have to fear a copy by the range expression because it is simply a pointer to a Person instead of the entire struct.

In fact, unless you either change the type to []*Person or index into the slice you won't be able to have changes reflected in the slice because a struct value will be a copy in the range loop. See https://github.com/golang/go/wiki/Range#gotchas but be aware that if the value is a pointer value, this isn't an issue.