01Notice when the resistance starts
Does the door catch before it closes, or does the handle become stiff afterwards? Does the key turn normally when the door is open? Those observations help describe the issue without guessing which part has failed. Avoid trying harder each time the lock resists. Assessment should look at the way the door meets its frame as well as the condition of the mechanism.
02Include any window faults in the enquiry
If a window also needs attention, describe it separately. A loose handle, a window stuck shut and an opening that will not lock can need different checks. Say how many are affected and whether access is straightforward. The mechanism needs to be identified before compatible parts can be confirmed, so the exact component and availability may not be known from a short message alone.