At my job they had two programs a 2016 and 2019 version, and I put all the billing statements for last month in 2016 not knowing that I had to use the 2019 version. Is there a way that I can transfer everything to the 2019 version with out messing anything up?
It depends on your current condition. Is your current data on 2016 = 2019 + billing statements for last months? If the answer is yes, you may create a backup copy of 2016 and restore it on 2019 as QuickBooks Team said earlier.