The best known tool, as per my earlier post is WiFi Manager, built by a Blynker called @tzapulica
Enter “github wifimanager” in Google and you are good to go. Look at the example with “parameters” that I believe already includes a Blynk token example.
If you have reasonable coding skills the best way is Blynk itself and this is one of many threads on the site that covers ways to do it Blynk App, to set esp8266-12e (Auth,ssid, and pass)