You can choose between two different URL formats for your form. Be careful, changing your form URL is not a reversible operation. Make sure to udpate your form URL everywhere where it's used.
If your users are going to see this url, you might want to make nice and readable. Example:
https://opnform.com/forms/contact
If your user are not going to see your form url (if it's embedded), and if you prefer to have a random non-guessable URL. Example:
https://opnform.com/forms/b4417f9c-34ae-4421-8006-832ee47786e7