Welcome e to Android Forums.
Two approaches ...
Go into the app drawer, select the app, and request uninstall. Do this for each app.
... or ...
Do a Factory Data Reset removing all apps and settings and then reinstall apps of interest. (If they are all from Play Store the reinstall will be pretty automatic but the settings will be lost.)
If the phone was out of your control and was root-ed it brings in a whole new collection of problems.
... Thom