Dear ondicastillo,
I suppose that you want to apply for the master's degree programm MIBAS.
In the online application you will be asked for backround knowledge in business administration and research methods. In the section
Upload you can then upload all relevant proofs p.e. transcript of records next to the recognition letter of your bachelor's degree.
Please look at
https://www.wiso.uni-hamburg.de/studien ... mibas.html
Your application documents will be checked directly in the faculty as part of the admissions process.
Best regards,
BK