Enter the 1095-A into the program.  Immediately below that, is the "Shared Allocation" boxes and you need to fill that out.

As for what percentages to enter, see "Allocation Situation 4" in the Instructions.  If everybody agrees, it is generally best to allocate 100% to one tax return and 0% to the other.

https://www.irs.gov/instructions/i8962#idm140053807732400