Laos doesn't required Visa if you're in ASEAN country such as Malaysia, Thailand, Cambodia, Singapore, etc. But required Visa if you live in non ASEAN countries such as USA, UK, China, etc.
Where to apply visa?
You can make Visa at Thailand side or Laos site. You need to pay for a fee around 40k Laotian kip/RM5 for a photo+ $35/RM148 to apply visa.
Visa is not required for Malaysian, Thai and all ASEAN citizens.