How many years do I have to study in College for Computer Engineering?

Depends where you go to school. In the US, for example, Americans have 13 years of education (K-12) prior to admission to university, and computer engineering is a 4-year degree. 6 years with bachelor + masters - which is more common these days as jobs are so hard to get.

Some places, it's a 3 year degree, and that's enough for that country's citizens to get work there. E.g. India. Such training is often unacceptable in other countries - not enough to get work, but more commonly, it's insufficient to qualify for an employment visa.

Your best bet with such a technical subject often is to study in your country of citizenship to meet local employers' requirements and make the essential contacts that net you a good job. Consider that carefully, although the US has really great education in that field. You WILL return to your country of citizenship to work. Student visas are always NON-immigration visas, and a requirement of issuing any such temporary, non-immigrant visa is that you intend to return to your country of citizenship.