Hello,
Here at the site of the forum realized that write a lot about XOOPS 2.3.0 and little about 2.0.18
which the latest
which the safest
which has more modules
Thanks

The latest release is 2.3. This release opens a new branch and merges 2 preexisting branches (2.0x/2.2x). From now, core devs are maintaining the 2.3 branch. Further release will be 2.3x releases, 3.x branch is being worked on too.
2.3 was released few days ago, it's stable for production but relatively new. For that reason, some minor bugs have been detected, those will be addressed soon within a 2.3.1 release.
About modules, only few modules do not work under 2.3, since this branch brings enhancements and prepares modules for next 3.0. Module dev have some adjustements to make in their modules, but "must have" modules and regularly maintained modules work already well with 2.3.
You could wait and make use of 2.0.18.2, but you will soon need to upgrade to 2.3, which will give you additional work. You'd better to start with 2.3 IMHO. It prevents you from further works.