Please help me

You need to help us by using more words to describe what you have, and what you need or are looking for.

A variable transformer (also known as a "variac") can be used to provide a variable input voltage. Then you can just use a simple AC voltmeter to measure the output. If it works correctly, the output voltage should remain within the specified variation.

It did it again. This showed as having zero answers until after I submitted mine. Then, sure enough, your answer from a few hours earlier magically appeared. It's baffling.

It is 150to250volt input and 220v output the menufacturer write on it 3000 watts but the transfarmer size in the voltagestablizer is very small there for I requst you that (3000 watts) how can I measure it
I use it for my refregerator

You could try hooking up a ~3000W load to it while measuring the voltage. I think hair dryers are often in the ~1500W range, so you could plug in two of them. Other household appliances like a clothes iron would work as well. You just need their total wattage to add up to around 3000. Plus, clothes irons and hair dryers are not likely to be damaged in any way in case the voltage drops excessively (as opposed to your refrigerator).

If you don't have an AC voltmeter, you can actually just use the sound of the hair dryer as an indicator of the voltage. The pitch of the sound should be proportional to the voltage, so if the stabilizer is working correctly, it should sound the same as the load increases.