There are many unique things about the Punjabi language with one of them being that it is the only fully tonal one in the Indo-European family. Given its specifics, you have to be very careful when choosing a Punjabi translation service. You have to go over all details to confirm that it has the quality which you require.
This language has seven different dialects. Majhi is the most widely used one in India and Pakistan, but it is not the only one. That is why you have to check exactly which dialect English to Punjabi translation has to be in. The second most important thing to find out is which writing script is required. Here the list of options is smaller. It includes the Gurmukhi and the Shahmukhi writing scripts. They are quite different so you must be extra careful not to make a mistake.
The next thing to think about is whether you will need to work with a Punjabi translator who is specialized in the field which your content is for. This is usually necessary for legal documents and ones related to products sold in the free market such as instruction and safety manuals. You should place the requirement for specialization at the top of the list as it is extremely important.
You have to check the qualifications of the professional for Punjabi to English translation and vice versa. The other factor for evaluating the quality of the service is the experience of the translator and more specifically the number and types of projects that he has worked on.