Thank you itonewbie
Because last year I used cloud based tax software. I and my assistant were working very helpful. My assistant input data and worked easy section, I reviewed at final and signed return
I change to proseries professional this year 2019 and want my assistant help me the same. Then my new customer on board supportteam  adviced me have vpn on my assistant pc . I searched vpn and understood like you explained that vpn only encrypt and secured files transfer from place to place
Therefore I think I still need private network and not define what it is:(
I asked my IT for help too but he told me costly for a small company
I have teamview and google remote access already but I still think it is not convenient for an live update return for each other. Other word , we have to transfer file via team view and open it and back and forth for each other
I work in CA and my assistant in TX
I might need two more tax preparers in CA
Can you suggest me further?
I appreciate this