Hi Jesus,
you can find all info about matlab certifications at: https://it.mathworks.com/services/training/certification.html
If you are enrolled to the "Matlab Fundamentals" course you should be able to access the course content at the Matlab Academy website: https://matlabacademy.mathworks.com/
As far as I know, this is the only material you can get, online sources. No pdf and others.
Once you have completed the course, you will be given a document saying that you have completed the "Matlab Fundamentals" course. This is not a certification, this is a necessary step to enroll the Matlab Associate Exam (see first link). Matlab Associate is the first level of certification you can get from Mathworks. Then Matlab Professional follows.
Massimo
