The html/template package is not a standalone package; it is a subpackage of the standard library's text/template system used for safely rendering HTML. Import it using import "html/template" and parse your template string with template.New followed by Parse.
package main
import (
"html/template"
"log"
"os"
)
func main() {
tmpl, err := template.New("example").Parse("<h1>Hello, {{.Name}}!</h1>")
if err != nil {
log.Fatal(err)
}
data := map[string]string{"Name": "World"}
err = tmpl.Execute(os.Stdout, data)
if err != nil {
log.Fatal(err)
}
}