Full stack web developer

Hello i would like to know everything i would need to know to become a full stack web developer. every course i need to study

It is not as simple as telling you everything you need to know because full-stack development is a vast space.

You could start with basic programming languages such as Python or Javascript, which are relatively simple languages that are pretty easy to learn and can get you started in terms of learning programming basics, as well as to help you with fundamentals such as design patterns, programming logic, and data structures.

After learning some fundamentals, you would need to decide what stack you would like to focus on as there are many options.

For Backend development you could learn Java → Spring, JavaScript → Node, C# → .NET, Python → Django to name a few popular choices.
Frontend development is usually done in Javascript, utilizing different frameworks or libraries such as React, Angular, or Vue to name a few popular choices.

You could ofcourse skip any aforementioned fundamentals, but learning the fundamentals is relatively important in order to help you make appropriate programming design/ implementation decisions, as yes you can build a web app with infinite if else conditions or loops to get it to work, but ultimately would result in more hard to debug issues or a web app that is hard or impossible to maintain. Learning the fundamentals is also important in terms of employability as you could stick to the same tech stack between jobs, but if you know the fundamentals, can make it easier to switch between languages as generally speaking the programming rules are similar between languages, with different syntax.