The importance of salt for hypertension is controversial, but eating less salt is usually included in the dietary advice to lower one's high blood pressure. Most likely, the effect of reduced salt intake varies between different people, being most important in elderly people or people with heredity for high blood pressure.
Generally speaking, an adult should not eat more than 5-6 grams of salt per day, that is, about one teaspoon. However most people eat much more than that often without being aware of it as most of the salt is hidden in processed meats, bread, toppings and take away.
It is a good idea to try to reduce salt intake as far as possible, especially if you have high blood pressure. A good start is to cut down on the salt when you cook and try not to salt the food extra at the table.