by far the easiest way is to just price your tickets with this cost in mind. If you had wanted $40 sell the tickets for $42 and your fees are more than accounted for.
Important note, in many states, it is illegal to pass the processing fee on to the end user so you will need to investigate that first.
if it is legal you can you would just add an item called "fee surcharge" that is variably priced and take your transaction total and multiply it by .0283 and enter that for the item price.
If swiping the card for a $100 sale
use 2.83%
$100*1.0283=$102.83
Charge $102.83 and your fee from square will be $2.83 netting $100
