In many cases, yes. These devices use common wiring terminals and can often be installed DIY with a small amount of work. Most models will come with the required mounting bracket, wall plugs and screws, and a trim plate that can be used to cover up any previous holes.
It’s important to determine what features your system has, and to match those with a thermostat that can support them properly. It’s also important to match the voltage requirements. Most thermostats use a standard 24V low voltage control system, but some systems, like baseboard heating, use high voltage and need specific models to run them.