Whether all invoices will have to be uploaded?

No. It depends on whether B2B or B2C plus whether
Intra-state or Inter-state supplies.
For B2B supplies, all invoices, whether Intra-state or Interstate
supplies, will have to be uploaded. Why So? Because
ITC will be taken by the recipients, invoice matching is
required to be done.
In B2C supplies, uploading in general may not be required
as the buyer will not be taking ITC. However still in order
to implement the destination based principle, invoices of
value more than Rs.2.5 lacs in inter-state B2B supplies will
have to be uploaded. For intra-state invoices below Rs. 2.5
lacs and all intra-state invoices, state wise summary will
be sufficient.