>Can I use any volts/watts charger for my phone?

No.

In general:

1. When we are talking chargers, we mean a device which converts AC electricity from a wall outlet, to DC electricity required by an electronic device
2. The charger must support the voltage and frequency of your residential electricity supply. Any significant deviation from that can damage the charger and/or present a fire hazard.
   1. Some chargers support a range of input voltages for international use
3. The charger's output voltage (Volts) must match the device's input voltage. Any significant deviation from that (more than about 10%) could damage the device, the charger, or be a fire hazard
4. The charger's output current (Amps) and/or power rating (Watts, equal to Volts x Amps) should be equal or greater than the device's required current/power rating. A device will only draw as much power as it needs.
   1. A lower current/power rating can mean the device charges slower or not at all.
   2. A significant lower rating can damage the charger or device.
5. A standard like USB is smarter than most chargers, generally speaking any charger supporting a USB standard (like USB 3.2) must support the minimum requirement, and higher currents and voltages can be supplied by both charger and device negotiating for it, you don't have to worry about incompatible electrical ratings causing damage.
6. The plug on the charger must also match the power jack on the device. Don't assume a plug and jack are compatible even if they physically fit and the power ratings are compatible; the polarity must also be consistent (especially an issue on barrel plugs).

Or TL;DR:

1. Use a charger compatible with your country.
2. The Voltage on the charger must match the device.
3. The Amps and/or Watts on the charger should be the same or greater than the device.
4. A charging standard like USB or Lightning is designed to simplify things for consumers so you don't have to worry about electrical ratings or causing damage.