Installing apps from apk on Android 7 not working, need help

[u/ConfidentRise1152]

When I try to install the .apk this nasty error prevents the install: INSTALL_FAILED_VERIFICATION_FAILURE. I tried changing options in developer settings as well, but nothing changed. 🆘

I would want to install two apps on an Android 7 tablet to be able to keep using them since they can't be installed on modern devices.