I need to copy some of the fields of existing sharepoint items and make some modifications into it ans save it as a new item.
In First screen (Form in View mode), I saved the selected item into the Collection.
In Second Screen (Form in New mode), I set up a default values of the fields i need to copy from collection I created in First screen including attachment field. All fields and attachments is defaulted into the new form and I can add new attachments which also shows all previous attachments. While saving by SubmitForm(NewFormCopy), everything is saved including newly added attachments but the attachments which is copied is not saved.
Do you want to modify an existing item or create a new item within your app?
I suppose that you want to create a new item within your app with copied Attachments from a collection, is it true? I have made a test and the issue is confirmed on my side.
The Attachments control lets users open files stored on a data source as well as add and delete files from a SharePoint list. Currently, we could only upload new attachments into a new SP list item via clicking Attach file button within the Attachments control.
If you want to create a new item within your app with copied Attachments from a collection, I afraid that there is no way to achieve your needs in PowerApps currently.
If you would like this feature to be added in PowerApps, please submit an idea to PowerApps Ideas Forum: