Once you create your ad, the URL cannot be modified. You can edit the title and content of the ad, but the link will remain the same as the original ad.
You can't change the tags either, but you can add new ones. If you need help creating your ad you can check it here.
Don't forget that you can also refresh your ad if you have a subscription plan, and if you don't have it you can buy a Boost. Please note that Boost is a service that is purchased in addition to unlocking or activating your job.