Hi Mohamed,

Yes you can delete but it get delete one by one and not all at a time.

1) Go to PE, Here you can see all your apps. 

2) Open any application and you can see there is Edit, Delete, Download etc options

3) Just click on delete, your application will get delete

see the image for reference

Hi Mohamed,

Hope this link will be helpful - https://success.outsystems.com/Support/Personal_Environment/Manage_the_database_space_of_your_personal_environment

Thanks