What does this even mean? Read it out loud.

The field 'Attachment' is not present on the screen 'Default Screen' configured for this issue.
To solve this problem, go to Screen 'Default Screen' configuration and add the field to the screen.
Alternatively, you can configure different screen for that issue by modifying the screen schemes associated with this issue:

• the Screen Scheme 'Default Screen Scheme', or
• the Issue Type Screen Scheme 'Default Issue Type Screen Scheme'