I am a History student researching on the history of Indo-China and African countries that were under French colonial rule. I did not find certain treaties like Franco-Lao treaty and others on the internet. Could someone guide me on where I could possibly find them on the internet.
They're scattered all over the internet. For example the Evian Accords for Algeria:
A large number of colonies simply voted to be independent:
Generally, an independence document is only needed if independence comes as part of a peace treaty at a conclusion of a war, when there are two parties to negotiate the terms. There is probably too much involved in setting up an independent government from scratch for a single document to be useful. And if the government has already reported the results of a referendum, anything further is unnecessary.