Two possibilities due to the different ways in which it is that the word “acousti-electric” is employed. If you are referring to an acoustic instrument that has an inbuilt pickup, then select the strings you would have for the instrument as if it were an acoustic instrument. Steel or Nylon, whatever type the guitar used prior to. However, you should purchase at the “acoustic” part of the aisle in the shop.
If these strings are made of steel they’ll likely be a bit heavier than the strings of a pure electric.
However when you refer to acoustic-electric, it might mean something that some refer to as an electric hollow body. In contrast to the solid body (like the Strat.). This time, you should focus on the electric guitar’s strings side.
The most significant difference will be that the electrical components tend to be a bit thinner. But either will exit the pickups perfectly.