Why do I have to always give my Apple ID password

when i simply want to update my apps no purchases just updates this thing pops up asking for my Apple ID password then it takes me to the billing page where my info and credit card information is wanting the 3 digit code on the back of the card I wont give itand then says purchase denied , but I wasn’t trying to purchase anything just update y apps the last time this happened in June some place tried to charge 701.00 to my card thank god the credit card company called and asked about it but I had to get a new card and that took a week all my money come on that card what the heck do I do