Which S32DS version are you using?
If 3.5 then the activation code should be visible in the main tab of your NXP user account download page for 3.5 product.
dumitrudaniel__0-1718286601899.png
If it's an older version (e.g. 3.4) then you need to click on the License Keys tab.
dumitrudaniel__1-1718286712023.png