How to check if a site is well protected?

We are preparing the launch of a new website, and we want to be sure that it is well protected from hacking. I've heard about a security testing service, when specialists check the site as if from the outside. I wonder who does this and how long it usually takes.

Before launching the site, it became clear that it would be better to do without vulnerability testing. I heard that penetration testing services help to identify weaknesses and prevent possible problems. I found a suitable option - they do everything professionally and with a clear report https://pharosproduction.com/penetration-testing-services