The impression is more it's a museum than a church with a living congregation. The fee of about 7 € gives you access to 1/the exhibition in the Cathedral and the Cathedral, 2/The tower with a great view of the area/Cadiz, 3/The nearby museum of the Catholic Cathedral. In the Cathedral you can read about the Cathedrals story and exhibited objects in Spanish and English, and also an audio track player stick is available + in more languages. It's not a place for prayer as it stands now. The walk up at the spiral pathway in the tower of the Cathedral is interesting and with no steps except just before the top. Here you meet the bells and watch out for your ears each quarter 🔔😉 If you see it all and read and listen to some or more you can easily spend 2 hours in the 3 places. The story is interesting in the overall line, but if you live in lets say Scandinavia you can skip some of the details and people mentioned.