Chadian passport holders do need to acquire a visa to enter Vietnam.

Chad is one of the countries in the world that does not have a Vietnamese embassy at the moment. And travelling to the location of the embassy of Vietnam in Countries Close to Chad such as Nigeria & Egypt quite hassle.

Is There any way to get visa for Vietnam without going to embassy?

Yes, you apply online for getting visa on arrival at international airport of Vietnam. There are many website providing service of consulting & supporting to get visa at arrival airport when you land in Vietnam & you just need to choose a reliable one to apply for your visa.