Objecting to planning applications can be done online. Your Local Planning Authority (LPA) gives access to viewing all planning applications that are submitted to anyone interested via their website. Objections to planning permission are visible on the LPA database, but you can request that your name and address are withheld.
However, if there is a chance that new development is going to be worked on in your local area and the planning officer that is assigned to the case deems it necessary to inform you because they believe that the new development may affect you, they will send a letter to your home directly presenting the proposed plans. Not all reasons that you may put forward will be considered as the grounds for the planning permission to be rejected – you need to make sure you are proposing a valid reason for the refusal.