There is no universal solution, but detecting the problem is very simple.
1. If you live in a larger space and signal is weak or absent in one part of it...
Your solution isa Range extender - a signal booster that will espand the signal by creating a new network trough obstacles. Signal quality depends on the amount and type of obstacles, i.e. walls. The best solution for this problem is the Mesh system, which is paired with a Cudy mesh router that supports this technology, and will expand the existing network without creating a new one and thus cover the entire household.
2. Do you have more devices than UTO connectors on the router?
Your soulution is a switch that will incrase the number od connectors and therefore the number of devices that van be connected.
3. Your computer doesn't have a built-in Wi-Fi adapter to the internet?
Your solution is a simple USB Wi-Fi adapter that plugs into your computer and connects to your home network after a simple installation.