What do you mean by a Wattage of an incandescent bulb?

Watt (\$W\$) is the unit of Power (\$P\$). There is an equation that says:

$$E = P \cdot t$$

You can see that Energy (\$E\$) equals Power (\$P\$) times time (\$t\$). There is a linear relationship between Energy and Power, so the higher the Power (wattage) of a device, the more energy it consumes.

The same formula, in a different form:

$$E=P \cdot t \rightarrow P=\frac{E}{t} \rightarrow W=\frac{J}{s}$$

One Watt means one Joule (\$J\$) per second (\$s\$) is being consumed. 60W means 60J/s is being consumed by the bulb.

Typical bulbs specify a wattage and a voltage. The figures together mean that when the indicated voltage is applied in free air in a room-temperature environment, the bulb's temperature and resistance will find an equilibrium state where the bulb consumes the indicated amount of electrical power (giving it off as some combination of conducted heat and radiated energy).

If a different voltage is applied to a bulb, the filament will reach a different equilibrium temperature and may, as a consequence, have a different resistance. If the resistance were constant, power would be proportional to the square of voltage, so a 10% reduction in voltage would represent about a 19% reduction in power. In practice, reducing voltage by 10% will reduce power by significantly less than 19%, but the reduction in visible light will be significantly greater than 19%. Although operating a bulb at at a lower voltage will greatly reduce efficiency, it will greatly improve longevity. There's a light bulb in San Francisco which doesn't burn very bright, but has been going almost continuously for over 100 years.

if you have 60W bulb, and your mains supply 220V then that means the bulb is drawing 60/220 = 0.273A of current.

So there must also be a voltage rating along with the wattage to be meaning full. Also, more is the wattage, more energy it consumes.