It is very uncommon to require planning permission for a Veranda. However, there are exceptions. The main times that planning permission is required is when you are installing to a listed building, the structure is larger than 50% of the land the original property covers
or if it is more than 3m in height.
If in doubt then it can pay to check with your local authority. The term "Veranda" is very ambiguous and can relate to a lot of other types of products unrelated to ours. It is always best to refer to it as a "Glass Canopy" or "Lean-to Roof" when making any enquiries.