My phone is downloading all kinds of apps without my permission

sometimes when you download one ap it opens the door for other apps to automatically download. I know that with a lot of the free apps you download you get a lot of ads that come with it that download to your phone. Check to see if maybe you are getting ads from one of your downloads. if you know how to navigate your file explorer see where these apps or ads are embedding themselves. As a tech one of the first questions i ask is were there any changes to your device before this issue. Like did you download a new app or did you change any piece of hardware, did you browse a website that you normally don't? those are just the basics there. I hope this helps you out some and you can resolve the issue soon.