main.go

package main

import (
	"fmt"
	"time"
)

func WellCome1(s string) {
	for i := 0; i < 5; i++ {
		fmt.Println(s, ":",i)
	}
}

func WellCome2(s string) {
	for i := 0; i < 5; i++ {
		fmt.Println(s, ":",i)
	}
}

func main() {
	go WellCome1("wellcome1")
	go WellCome2("wellcome2")
	time.Sleep(200*time.Millisecond)
	fmt.Println("hello main ")
}

result

wellcome1 : 0
wellcome1 : 1
wellcome2 : 0
wellcome1 : 2
wellcome1 : 3
wellcome1 : 4
wellcome2 : 1
wellcome2 : 2
wellcome2 : 3
wellcome2 : 4
hello main