I want to know if this is legal to get a driving licence by exchange

For a full driver’s license. I’m interested in using their services, but I have a few questions before proceeding. Can you provide more information about the website eudriverlicence.com? Is the process they offer legal and legitimate? What is the experience and expertise of the lawyers involved in facilitating driver’s license exchanges? Are there any specific requirements or documentation needed for the process? How long does the entire process typically take? Do they offer any guarantees or refunds if the license exchange is not successful? Are there any limitations or restrictions based on nationality or country of origin? What are the fees associated with their services? Is there any ongoing support or assistance provided after the license exchange is completed?

In Sweden, it is simple, only EEA and Japanese license may be exchanged without test.
Other EU countires, e.g., Luxembourg, Belgium or France, may provide more alternatives however it is always required you have a residence permit and a local ID in that particular EU country.

Therefore, either you pass the tests here in Sweden, or you are prepared to afford being a resident in another EU country for at least 1 year (multiple air tickets, rental agreement for 1 year, or even completely move from Sweden to other EU countries, etc)

Very likely a legal EU driving license should carry your Biographical data, meaning you should be required to go to the local authorities to have fingerprint collected, for example:
www.consilium.europa.eu/prado/en/LUX-FO-01010/index.html

If they claim they will provide you another EU license without you physically being there, it is for sure a scam and you should run :P

Funny they claim their main service is immigration even before they started driving license business, however noting on their website is indicating that they have experience in immigration at all, only a very ugly webpage talking about driving license, with a few dead hyperlinks though

To exchange is of course legal, but I doubt if they help you to exchange, or just buy a fake license and charge you extra