I guess now paper Factura C is not available for everyone, that depends on your AFIP category.
I am creating Factura E for each payment right now and usually using Nubi (tunubi.com)
I suggest looking for an accountant at least to set up things. Factura E is IIBB tax exempt (for now...) but Factura C not, so you need to pay IIBB.
Upwork direct to a local bank in ARS exchange rate is really bad (around 6% less than the market) and they do a deposit through an ATM so the bank discounts you 1% in the concept of "impuesto al cheque".
Nubi rate is of around 4.5%, no extra charges, and you can get USD.
Hope this helps you.