If your devices connect to WiFi fine, but they do not obtain internet that way, then you may have a problem with your WiFi router box or modem-router box.
I suggest as the best first thing to try, that you go to the WiFi box, and unplug it from just the power, for 10 or 20 minutes at least. That will allow it to cool, and reset a bit.
After that time, plug it back into the power, please, and wait 5 minutes, before trying to connect to WiFi and internet.
That procedure sometimes gets this sort of situation back into working order.
If it fails to improve the situation, please tell me more, after trying it, about what internet provider and local network boxes you have, and I will advise you further toward a solution.