Carrying Fields

I have two Tables and two Forms. Table 1 is related to Form 1. Table 2
is related to Form 2. On Form 1, there's a command button that opens
Form 2. I want the auto number from Form 1 to transfer to Form 2, when
I click on the command button. To make it simple, I want the field in
one table to be forwarded to another field in a dirferrent table.