I´m using Electrum just on Laptop. So, I need to make a transfer to Binance (BTC), but they say, it must be the network: SEGWITBTC.
Were do I find the option to select this network. I´m using latest version of Electrum 4.5.8 (portable).
Well, first of all, SegWit is not a network but an address format.
Go to your Electrum, open the Receive tab, and generate a permanent address for receiving transactions. It will be in the Segregated Witness (SegWit) format and should start with bc1.
In case of sending coins, go to the Send tab in Electrum, enter your Binance deposit wallet address in the Pay to field, and specify the amount in mBTC. Then click Pay, choose the fee (according to bitcoinfees.net, the current average fee is ~2.02 sat/vB), and send the transaction.
However, your question remains somewhat unclear to me.