This is entirely up to you. There are so many different types of toothpaste that it can make choosing one rather difficult. We all have our own preferences when it comes to toothpaste and tend to base our choice on price and taste.
As a starting point, you will find that most toothpaste contains fluoride which does protect the teeth against tooth decay. So, go for fluoride toothpaste.
If you suffer from sensitive teeth then there are toothpastes available which can help to prevent this.
Another increasingly popular type is the ‘whitening toothpaste’ which can help stained or discoloured teeth. However, they will only remove mild level stains. If your teeth are heavily stained then you may need professional teeth whitening via your dentist or a home whitening kit.