Pero pag sinabing qr code generator means, na ikaw mag lalagay ng text/phrase para mga maging qr code yung text using yung app/website, in which pag may mga backdoor ito it will send all the text to attacker's servers na linagay mo sa app/website or yung mas famous is pinapalitan yung text na linagay mo which is famous siya for crypto wallet address na ginagawang qr code.
So, I suggest na only use qr code generator na open source, used and trusted by many, or mas maganda if gawa mo since may mga free scripts naman a pwedeng ma google and sa github