Can you check your download history to see? It could be steam redistrubutiles as they are required for some games to play, and yes, it does show up in the downloads history. You can see them under "MANAGE DOWNLOADS" at the bottom of the app.

Also, are you in a family sharing? Perhaps someone else is downloading stuff in your house without telling you in your family.

If none of the above is what is happening to you, you may have someone nefarious on your account doing stuff. In this case, it is best to scan your pc for viruses and phishing malware.

Mate I have been using steam for years there isn't any download when I go to manage downloads there isn't anything getting download. There isn't anyone using family share in my account

Then you may have a nasty person doing nasty things with your account. You know how many scams and phishing people do on steam if you been here for years, so best to scan with malwarebytes or ESET free scanning tool to make sure.

You can also check your logins to see if someone is logging into your account you do not recognize.

Thx mate fo the help

pues que mal