With a blocked account you can prove sufficient financial means in the visa procedure.
You can choose where you want to set up your blocked account. It is important that the following requirements are met:
The blocked account must contain sufficient funds to cover the costs incurred for the duration of the planned stay in Germany, unless other proof of financing is also submitted in the visa procedure. Certain standard rates apply. For students, the amount to be proven is currently 11,208 EUR / year, which must be paid into the blocked account when applying for a visa. The account may only allow the withdrawal of a certain amount per month (for students 934 EUR).
The blocked account may be closed only with the consent of a blocking beneficiary. The blocking beneficiary is either the foreign mission or, after entry, the competent foreigners authority. A blocked account therefore only ensures that sufficient funds are always available to secure subsistence. It does not entitle the blocking beneficiary to access the blocked account.
More information is provided here.