Jojeeka,
Sorry that you are seeing this issue.
Can you please go to Window > Preferences > MyEclipse > Subscription, click on ‘Enter Subscription’ and see if the fields are editable ?
Alternatively you can go to the <USER_HOME> directory,edit the .myeclipse.properties file and manually add the License key and Licensee details. Restart the IDE and see if the changes are reflected.
Here is an FAQ on the location of MyEclipse files and folders :
https://www.genuitec.com/forums/topic/installation-where-are-the-myeclipse-files-and-folders/
If you are still seeing issues, please try switching to a new workspace and see if the Subscription details are editable.If the issue persists, please share the OS and version details. Also please check the .log file which is located at <workspace dir>/.metadata/.log for any errors of interest.
Let us know how it works for you.