Its very simple. let's start with how to get this error I'm assuming you already have installed go lang in your machine.

🚀Step 1:-

Now just go to desktop and create a folder called go lang and open that in VS Code.

🚀Step 2:-

Create a folder called cards inside there create main.go and paste the following code given below

package main
import (
    "fmt"
)
func main() {
    // var card string = "Ace of Spades"
    cards := []string{"Ace of Diamonds", newcard()}
    cards = append(cards, "Six of shades")

    for i, card := range cards {
        fmt.Println(i, card)
    }
}
func newcard() string {
    return "Five of Demonds"
}

🚀Step 3:-

in Golang folder create a file called cs.go and paste the code below

package main
import (
    "fmt"
)
func main() {
    cards := "Ace of shades"     
    fmt.Println(cards)
}

The Folder would look like this

🚀Step 4:-

Now open the terminal and in problem you see the error looks like this

🚀Step 5: -

Let's fix this. Now go back to the terminal and see your path. and type

cd cs

🚀Step 6: -

Now you are in cs directory. Run

go mod init cs

Save this file CTRL +S. See Error is gone.

Enjoy and give a red/pink heart if it helps you fix the issue. happy Coding.