Under Project service:
And under project template:
There is a possibility of customizing forms in Microsoft Dynamics CRM, through Customize entity:
Also, seems like we can add a new field as well:
to forms:
I see that there is no file field in the forms:
Is there a way to allow file upload in Microsoft Dynamics CRM forms?
Maybe programmatically?
If you have Notes enabled on the entity, you can upload files via the notes component on the form.
To enable it, go to the entity customization and check the Notes box, and then add notes to your entity form. Now you can upload files on the entity form by adding a new note on the record, through the newly added Notes component.
Picture guide: https://i.sstatic.net/Xwjrd.jpg
An alternative is using something like SharePoint instead to host your files, and using the standard CRM/SharePoint integration to access them in CRM. That way you won't use up all your expensive CRM storage with files.