I already said it, you get a list of UTXOs and you can spend as many of them as you want.
Each bitcoin transaction has an array of inputs and an array of outputs that have to have at least one item in them (one input and one output) but you can create a transaction with for example 10 inputs and 4 outputs.
Oh, it seems that I know nothing at all. I thought transaction inputs are addresses like they appear on block explorers. Anyway thank you guys I'm investigating this again.