For a particular document library in SP 2013 when i try to upload documents, the dialog box to enter the properties is hidden/trimmed. What can be the issue?
Form fields may be hidden in EditForm.aspx of library. Navigate to EditForm.aspx page and append your item ID
For example https://your site Url/libary name/Forms/EditForm.aspx?ID=Item ID
Edit that page and see if there is any script editor/content editor web part added to hide fields.
Another way is with the help of SharePoint designer. Open a particular library, in that you can see the edit form.aspx and then check any code added to hide.
It could be the configuration of the columns in the list. Are you able to provide a screenshot of the columns that you expect to add? Are they hidden perhaps (do they show as hidden against the relevant content type in the UI, or they may be hidden in code)?