When trying to determine what a car is legally allowed to tow, the principle factors are weights, and they are basically determined from the data on the cars weight plate, for cars sold in the EU.
Here is an example of the layout of the plate
The first three lines define the make and model with its unique VIN number.
The top figure marked "kg"is the Gross Vehicle Weight (GVW) or maximum limit for the weight of the solo car when fully loaded.
The next figure marked "kg"is the Gross Train Weight (GTW) or maximum limit for the weight of the car when fully loaded and the weight of any trailer.
The third and fourth lines marked kg are the front and rear car axle load limits'
The difference between GTW - GVW = the maximum weight any trailer can be when the car is fully loaded, and is usually the same as the manufacturers specified maximum towed weight limit - Though some do quote a greater figure on the understanding the car may not be fully loaded, so some of the unused payload can be transferred to the trailer, but at all times the combined weights must not exceed the GTW.
It is illegal to load a solo car beyond its GVW and car and trailer beyond the GTW limit. or indeed to exceed any of teh stated axle limits - all these stamped values are absolutes.
That's the legal bit, now the UK caravan industry offers some advice. It is widely recognised that towing a caravan behind any car is going to push the cars capabilities. Bearing in mind the size and weight of a caravan, it is sensible to not push the limits of the car. So for an experienced caravanner, the advice is to choose a caravan whose maximum weight does not exceed the kerbweight of the car.
When it's a novice the advice reduces the maximum weight of the caravan to not exceeding 85% of the Kerbweight.
The manufacturer may publish the cars expected kerbweight in the handbook. If not you can use the car's Mass in Service figure from the V5c document which is close to the value of Kerbweight
These advisory values are just advice, they carry no legal power, they offer no guarantees of good or safe towing
For simplicity if you choose a caravan whose MTPLM matches or is lower than the advisory weight (and is still within the legal limits) then there is a fair chance it will tow reasonably, however when it comes to smaller cars there is less flexibility in the choices of caravans.
Good towing is the result of safe loading, ensuring the car and trailer are in full working order, tyre pressures are set correctly and good driving habits.