No, the 123D apps are no longer available—the 123D suite of products was discontinued in April 2017. This strategic decision came from a desire to simplify Autodesk’s portfolio and consolidate key features into apps such as Tinkercad, Fusion 360, and ReCap Pro.
Here's a summary of the 123D apps and their replacements:
123D Design was replaced by Tinkercad, a free web-based 3D modeling tool.
123D Sculpt was replaced by Fusion 360, a professional-grade 3D modeling, CAD, and CAM software.
123D Make was replaced by Fusion 360, which offers similar tools for creating 3D printable designs.
123D Catch was replaced by ReCap Pro, a professional-grade 3D scanning and photogrammetry software.
If you were a user of the 123D apps, you can still access your old projects and designs through the Autodesk 360 cloud storage platform. However, you will no longer be able to create new projects in the 123D apps.