I could be the most normal, but I still do not understand, it happens that I am just starting in the world of cryptocurrencies and I invested a not very high amount in them, for that I bought bitcoins in a page that allowed me to buy with local currency, everything well that I transferred to the wallet (electrum) since I realized that I was transferred a part less than the total amount, when reviewing the transaction I realized that it was separated in 2 one that came to my wallet and another went to another part (which is the one that has the most money), also said address starts with 3 and not with 1 as are the normal bit addresses, besides this output was labeled as not spent, even though I do not figure in nowhere.

transaction number 1b69c174f6d2e151ed984c30e0ecb75f23a027c38f7c34cf201dbdd893ead93d

please help,