No save option

I try to save a Dorico score on my Ipad , click the export button, choose “Dorico project” , but there is no option anymore to save it. Whats going on here?

There is no Save command in the iPad version. Everything you do is auto-saved, as is standard for iOS apps. See this thread from last year for discussion.

The options in the Share sheet are to some degree determined by iPadOS itself: we don’t control whether or not the Save To Files option appears. My understanding is that this option only appears if the project is not located in iCloud Drive.

So, how does it work, when I open a score from the ICloud? Will it be automatically saved in the ICloud or on the IPad?

Dorico will save the project to whatever location it opened up from, so if you open it from iCloud, it will be saved directly back to iCloud.