Your uPVC door shouldn’t need adjusting at all after it has been installed but if it does, it is better to get your installer to do it. There are many different hinges with many different parts to them that the installer will know about and how to do them.
The door and frame should be seen as a single system with the various components designed to work perfectly with each other - this is why in almost all cases; a new door requires a new frame to be fitted with it. When the door is installed, it will be tuned to a perfect fit and fastened tightly in place so that it should not move in the future.
In order to seal and lock correctly, the locking system needs to be precisely aligned between the frame and door. If the system is not working correctly, then the bolts may not slide into place easily, in which case the lock will feel stiff and may not engage correctly.
Unlike wood or other materials, UPVC does not warp or change size during different types of weather, so it has a closer fit than older doors giving a better seal against draughts. In the unlikely event that a door becomes misaligned, then the installer will need to measure the frame and door to identify why it is no longer functioning correctly before making any adjustments or, if the door shas become misaligned due to a failure, recommend a replacement to keep your home secure.