Choose what it suits you most.

The Standard option will create a Legacy wallet usually with an address starting with 1. This is the normal bitcoin wallet which was used since the beginning of Electrum. Fees are higher though.

The Segwit option will create a Segwit wallet where addresses starts differently but this option make transactions with low fees. I haven't tried it myself as I am only using Standard. Someone else can add to this reply and explain you in detail what Segwit does except lower fees.